Apparatus for connecting a longitudinal member to a bone portion

ABSTRACT

An apparatus includes a fastener engageable with a bone portion to connect a longitudinal member to the bone portion. A housing has a first passage configured to receive the longitudinal member and a second passage extending transverse to the first passage. The fastener extends through an opening in the housing into the second passage. The second passage includes a plurality of frustoconical surfaces for engagement with the fastener.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority to U.S. ProvisionalPatent Application No. 60/701,214 (filed Jul. 20, 2005), and is acontinuation-in-part of PCT Application No. PCT/US2005/038019 (filedOct. 20, 2005), the entire contents of which are hereby expresslyincorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This application relates to surgical systems and assemblies that includean access device for minimally invasive surgery, and in particularrelates to systems and devices that provide access to a surgicallocation, e.g. adjacent a spine, for one or more instruments to performa procedure at the surgical location. More particularly, thisapplication relates to an apparatus which can be used to retain boneportions, such as vertebrae of a spinal column, in a desired spatialrelationship.

2. Description of the Related Art

An apparatus for retaining vertebrae of a spinal column in a desiredspatial relationship includes a longitudinal member extendable along thespinal column. A fastener engageable with a vertebra of the spinalcolumn connects the longitudinal member to the vertebra. A housing has afirst passage through which the longitudinal member extends and a secondpassage with a longitudinal axis extending transverse to the firstpassage. The fastener extends through an opening in the housing into thesecond passage. The longitudinal axis of the fastener is positionable inany one of a plurality of angular positions relative to the longitudinalaxis of the second passage.

A spacer received in the housing is engageable with the fastener and thelongitudinal member. A clamping member threadably engages the housing toclamp the longitudinal member, the spacer, and the housing to thefastener to prevent movement of the fastener relative to the housing.

SUMMARY OF THE INVENTION

In one embodiment, polyaxial screws and apparatus comprising such screwswhich may be used to retain bone portions in a desired spatialrelationship are provided. The apparatus includes a longitudinal memberconnectable with a bone portion. A fastener having a longitudinal axisis engageable with the bone portion to connect the longitudinal memberto the bone portion. A housing has a first passage configured to receivethe longitudinal member. The housing has a second passage with alongitudinal axis extending transverse to the first passage. Thefastener extends through an opening in the housing into the secondpassage and is movable relative to the housing. The longitudinal axis ofthe fastener is positionable in any one of a plurality of angularpositions relative to the longitudinal axis of the second passage.

A spacer received in the second passage of the housing is engageablewith the fastener and the longitudinal member. A spring memberengageable with the spacer applies a force to prevent relative movementbetween the fastener and the housing when the longitudinal member isdisengaged from the spacer and the spacer engages the fastener. Thefastener and the housing are manually movable relative to each otheragainst the force when the longitudinal member is disengaged from thespacer and the member applies the force. The spring member is an archedring-shaped member with diametrically opposite sides bent toward eachother when the spring member is disengaged from the housing and thespacer. A clamping mechanism clamps the longitudinal member, the spacerand the housing to the fastener to prevent movement of the fastenerrelative to the housing.

In accordance with another embodiment, the apparatus includes alongitudinal member connectable with a bone portion. A fastenerengageable with the bone portion has a longitudinal axis and connectsthe longitudinal member to the bone portion. A housing has a firstpassage through which the longitudinal member extends. The housing has asecond passage with a longitudinal axis extending transverse to thefirst passage. The fastener extends through an opening in the housinginto the second passage and is movable relative to the housing. Thelongitudinal axis of the fastener is positionable in any one of aplurality of angular positions relative to the longitudinal axis of thesecond passage. A spacer received in the second passage of the housingis engageable with the fastener and the longitudinal member. The spacerincludes an axially extending portion extending from a surface engagingthe fastener. The axially extending portion is spaced from the fastener.A clamping mechanism clamps the longitudinal member, the spacer, and thehousing to the fastener to prevent movement of the fastener relative tothe housing.

In accordance with another embodiment, an apparatus includes alongitudinal member connectable with a bone portion. A fastenerengageable with the bone portion has a longitudinal axis and connectsthe longitudinal member to the bone portion. A housing has a firstpassage through which the longitudinal member extends. The housing has aradially outwardly extending surface. The radially extending surfacedefines a circumferentially extending groove. The housing includes athread extending axially from an upper surface of the housing to thegroove. A clamping mechanism threadably engageable with the thread onthe housing clamps the longitudinal member to the housing to preventmovement of the rod relative to the housing.

In accordance with another embodiment, the clamping mechanism is a capscrew that includes a boss extending between threads of the cap screwand a lower surface of the cap screw. The cap screw threadably engagesinternal threads on the housing to apply a downward force against therod. The internal threads of the housing terminate above the level ofthe rod. In another embodiment, the housing also has grooves providedbelow the internal threads. In this embodiment, the grooves are alsoprovided above the level of the rod.

In accordance with another embodiment, the cap screw includes a bottomsurface configuration adapted to provide asymmetrical contact pointsagainst the rod on opposite sides of the passage receiving the rod. Inanother embodiment, the cap screw engages the rod at two points on oneside of the passage, and at one point on the other side of the passage.The bottom surface configuration may include a first annular protrusionforming a ring, and a second semi-annular protrusion forming an archaving the same center as the first annular protrusion.

In accordance with another embodiment, a housing has a passage throughwhich the fastener extends with a plurality of generally frustoconicalsurfaces. In another embodiment, a first generally frustoconical surfaceis provided adjacent an opening at a lower end of the housing, and asecond generally frustoconical surface is provided below the firstgenerally frustoconical surface. The first generally frustoconicalsurface may be inclined relative to a longitudinal axis of the housingat an angle less than that of the second generally frustoconicalsurface. Additional frustoconical surfaces may be provided, with theangle of incline relative to the longitudinal axis increasing toward theopening at the lower end. The angle of incline may range from about 2degrees to about 30 degrees or more. Each of the generally frustoconicalsurfaces may be separated by a curved portion or a groove.

In another embodiment, an apparatus is provided comprising a fastenerand a housing. The housing has a first passage through which alongitudinal member extends, and a second passage transverse to thefirst passage through which the fastener extends. A pair of jaws areprovided within the housing and positioned about a head of the fastener.The jaws may be pivotally connected to the housing, more preferablyusing pivot pins extending through apertures in the housing and thejaws. The housing includes internal threading above the diameter of thelongitudinal member, adapted to engage a cap screw that may be insertedinto the housing to apply a force against the longitudinal member, thejaws or both.

In one embodiment, the jaws may have lower contact surfaces thatgenerally conforms to the shape of the head of the fastener. This lowercontact surface may be spherical. The jaws may also have medial contactsurfaces that are generally cylindrical, upon which the longitudinalmember may rest. Upper contact surfaces of the jaws may be conicallyshaped, adapted to conform to a boss extending below the threads of thecap screw.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objects, features and advantages of the invention will becomeapparent from the following detailed description taken in conjunctionwith the accompanying figures showing illustrative embodiments of theinvention, in which:

FIG. 1 is a perspective view of one embodiment of a surgical system andone embodiment of a method for treating the spine of a patient.

FIG. 2 is a perspective view of one embodiment of an access device in areduced profile configuration.

FIG. 3 is a perspective view of the access device of FIG. 2 in a firstenlarged configuration.

FIG. 4 is a perspective view of the access device of FIG. 2 in a secondenlarged configuration.

FIG. 5 is a view of one embodiment of a skirt portion of an accessdevice.

FIG. 6 is a view of another embodiment of a skirt portion of an accessdevice.

FIG. 7 is a perspective view of another embodiment of an access devicein an enlarged configuration.

FIG. 8 is an enlarged sectional view of the access device of FIG. 7taken along lines 8-8 of FIG. 7.

FIG. 9 is a sectional view of the access device of FIG. 7 taken alonglines 9-9 of FIG. 7.

FIG. 10 is a perspective view of another embodiment of an access devicein an enlarged configuration.

FIG. 11 is an enlarged sectional view of the access device of FIG. 10taken along lines 11-11 of FIG. 10.

FIG. 12 is a sectional view of the access device of FIG. 10 taken alonglines 12-12 of FIG. 10.

FIG. 13 is a view of a portion of another embodiment of the accessdevice.

FIG. 14 is a view of a portion of another embodiment of the accessdevice.

FIG. 15 is a sectional view illustrating one embodiment of a stage ofone embodiment of a method for treating the spine of a patient.

FIG. 16 is a side view of one embodiment of an expander apparatus in areduced profile configuration.

FIG. 17 is a side view of the expander apparatus of FIG. 16 in anexpanded configuration.

FIG. 18 is a sectional view of the expander apparatus of FIGS. 16-17inserted into the access device of FIG. 2, which has been inserted intoa patient.

FIG. 19 is a sectional view of the expander apparatus of FIGS. 16-17inserted into the access device of FIG. 2 and expanded to the expandedconfiguration to retract tissue.

FIG. 20 is an exploded perspective view of one embodiment of anendoscope mount platform.

FIG. 21 is a top view of the endoscope mount platform of FIG. 20 coupledwith one embodiment of an indexing arm and one embodiment of anendoscope.

FIG. 22 is a side view of the endoscope mount platform of FIG. 20illustrated with one embodiment of an indexing arm and one embodiment ofan endoscope.

FIG. 23 is a perspective view of one embodiment of an indexing collar ofthe endoscope mount platform FIG. 20.

FIG. 24 is a perspective view of one embodiment of an endoscope.

FIG. 25 is a partial sectional view of one embodiment of a stage of oneembodiment of a method for treating the spine of a patient.

FIG. 26 is a perspective view of one embodiment of a fastener.

FIG. 27 is an exploded perspective view of the fastener of FIG. 26.

FIG. 27( a) is an enlarged side view of one embodiment of a biasingmember illustrated in FIG. 27 taken from the perspective of the arrow 27a.

FIG. 28 is a perspective view of one embodiment of a surgicalinstrument.

FIG. 29 is an enlarged sectional view of the fastener of FIGS. 26-27coupled with the surgical instrument of FIG. 28, illustrating oneembodiment of a stage of one embodiment of a method for treating thespine of a patient.

FIG. 30 is side view of one embodiment of another surgical instrument.

FIG. 31 is a partial sectional view of one embodiment of a stage of oneembodiment of a method for treating the spine of a patient.

FIG. 32 is a side view of one embodiment of another surgical instrument.

FIG. 33 is a perspective view similar to FIG. 31 illustrating theapparatuses of FIGS. 26 and 32, in one embodiment of a stage of oneembodiment of a method for treating the spine of a patient.

FIG. 34 is an enlarged sectional view of the apparatus of FIGS. 26 and32, illustrating one embodiment of a stage of one embodiment of a methodfor treating the spine of a patient.

FIG. 35 is an enlarged sectional similar to FIG. 34, illustrating oneembodiment of a stage of one embodiment of a method for treating thespine of a patient.

FIG. 36 is an enlarged view in partial section illustrating oneembodiment of a stage of one embodiment of a method for treating thespine of a patient.

FIG. 37 is a partial view of illustrating one embodiment of a stage ofone embodiment of a method for treating the spine of a patient.

FIG. 38 is a perspective view of a spinal implant or fusion deviceconstructed according to another embodiment showing a first side surfaceof the spinal implant.

FIG. 39 is a perspective view of the spinal implant of FIG. 38 showing asecond side surface of the spinal implant.

FIG. 40 is a plan view of the spinal implant of FIG. 38 showing an uppersurface of the spinal implant.

FIG. 41 is a side view of the spinal implant of FIG. 38 showing thefirst side surface.

FIG. 42 is a cross-sectional view of the spinal implant taken along theline 42-42 in FIG. 41.

FIG. 43 is a perspective view of another embodiment of a spinal implantconstructed according to another embodiment showing a first side surfaceof the spinal implant.

FIG. 44 is a perspective view of the spinal implant of FIG. 43 showing asecond side surface of the spinal implant.

FIG. 45 is a plan view of the spinal implant of FIG. 43 showing an uppersurface of the spinal implant.

FIG. 46 is a side view of the spinal implant of FIG. 43 showing thefirst side surface.

FIG. 47 is a cross-sectional view of the spinal implant taken along theline 47-47 in FIG. 46.

FIG. 48 is a view showing a pair of the spinal implants of FIG. 38 infirst relative positions between adjacent vertebrae.

FIG. 49 is a view showing a pair of the spinal implants of FIG. 38 insecond relative positions between adjacent vertebrae.

FIG. 50 is a view showing the spinal implant of FIG. 43 between adjacentvertebrae.

FIG. 51 is a view showing a spinal implant being inserted between theadjacent vertebrae according to another embodiment.

FIG. 52 is a side view of an apparatus according to another embodiment.

FIG. 53 is a front view of the apparatus of FIG. 52.

FIG. 54 is a top view of the apparatus of FIG. 52.

FIG. 55 is a back view of the apparatus of FIG. 52.

FIG. 56 is a bottom view of the apparatus of FIG. 52.

FIG. 57 is a sectional view of the apparatus of FIG. 52, used inconjunction with additional structure in a patient.

FIG. 58 is a longitudinal sectional view of the apparatus of FIG. 57taken from line 58-58 of FIG. 57.

FIG. 59 is a transverse sectional view of the apparatus of FIG. 58 takenfrom line 59-59 of FIG. 58.

FIG. 60 is a sectional view, similar to FIG. 57, illustrating analternative position of the apparatus of FIG. 52.

FIG. 61 is a sectional view, similar to FIG. 57, illustrating anotheralternative position of the apparatus of FIG. 52.

FIG. 62 is a transverse sectional view of the apparatus of FIG. 61,taken along lines 62-62 of FIG. 61.

FIG. 63 is a side view, similar to FIG. 52, of another apparatus.

FIG. 64 is a front view, similar to FIG. 55, of the embodiment of FIG.63.

FIG. 65 is a sectional view, similar to FIG. 57, of the apparatus ofFIG. 63, used in conjunction with additional structure in a patient.

FIG. 66 is a transverse sectional view of the apparatus of FIG. 63,taken along lines 66-66 of FIG. 65.

FIG. 67 is a perspective view of an access device according to anotherembodiment.

FIG. 68 is a side perspective view of the access device of FIG. 67.

FIG. 69 is a perspective view of the access device of FIG. 67 in apivoted configuration.

FIG. 70 is an end view of the access device of FIG. 67.

FIG. 71 is an exploded perspective view of the access device of FIG. 67in an expanded configuration with some portions shown in hidden line.

FIG. 72 is a perspective view of the access device of FIG. 67 in acontracted configuration with some portions shown in hidden line.

FIG. 73 is a partial sectional view of the access device of FIG. 67 inan early stage of a procedure.

FIG. 74 is a perspective view of a portion of one embodiment of asurgical system that includes an access device, a support arm, and alighting element shown applied to a patient.

FIG. 75 is a perspective side view of the surgical system of FIG. 74shown applied to a patient.

FIG. 76 is a top view of the surgical system of FIG. 74.

FIG. 77 is a perspective view of one embodiment of a lighting element.

FIG. 78 is a perspective view of another embodiment of a lightingelement.

FIG. 79 is a perspective view of another embodiment of a lightingelement.

FIG. 80 is a perspective view of an access assembly.

FIG. 81 is an exploded perspective view of the access assembly of FIG.80.

FIG. 82 is a side view of an access device of the access assembly ofFIG. 80, the access device having a lock to maintain a state ofexpansion thereof.

FIG. 83 is a cross-sectional view of the access device of FIG. 82 takenalong section plane 83-83.

FIG. 83A is a detail view of one embodiment of a lock to maintain astate of expansion of an access device, the lock shown in the lockedposition.

FIG. 83B is a detail of the lock of FIG. 83A, the lock shown in theunlocked position.

FIG. 84 is a cross-section view similar to that of FIG. 83 with the lockdevice in the unlocked position during the un-expansion of the accessdevice.

FIGS. 85 and 85A are top perspective and detailed views respectively ofthe access device of FIG. 82 with the lock in a locked position.

FIGS. 86 and 86A are top perspective and detailed views respectively ofthe access device of FIG. 82 with the lock in an unlocked position.

FIG. 87 is a top view of a viewing element mounting assembly having alight post mount or visualization mount, according to one embodiment.

FIG. 88 is a side view of the viewing element mounting assembly of FIG.87.

FIG. 89 is a perspective view of the light post mount or visualizationmount of FIG. 87.

FIG. 90 is a top view of the light post mount or visualization mount ofFIG. 89.

FIG. 91 is a side cross section view of the light post mount orvisualization mount of FIG. 89.

FIG. 92 is a bottom view of the light post mount or visualization mountof FIG. 89.

FIG. 93 is a side view of a support portion of the light post mount orvisualization mount of FIG. 89.

FIG. 94 is a schematic view of the cross section of a passage of thelight post mount or visualization mount of FIG. 89.

FIG. 95 is an end view showing a spline surface of a spline ring for thelight post mount or visualization mount of FIG. 89.

FIG. 96 is a side view of the spline ring of FIG. 95.

FIG. 97 is another end view of the spline ring of FIG. 95.

FIG. 98 is a top view of a light post or visualization element,according to one embodiment.

FIG. 99 is a side view of the light post or visualization element ofFIG. 98.

FIG. 100 is a front view of a light post mount block or visualizationelement mount block, according to one embodiment.

FIG. 101 is a side view of the light post mount block or visualizationelement mount block of FIG. 100.

FIG. 102 is a top view of the light post mount block or visualizationelement mount block of FIG. 100.

FIG. 103 is a side cross section view of the light post mount block orvisualization element mount block of FIG. 100.

FIG. 104 is a back view of the light post mount block or visualizationelement mount block of FIG. 100.

FIG. 105 is a top perspective view of the light post mount block orvisualization element mount block of FIG. 100.

FIG. 106 is a bottom perspective view of the light post mount block orvisualization element mount block of FIG. 100.

FIG. 107 illustrates a pin configured to be coupled with the light postmount block or visualization element mount block of FIG. 100.

FIG. 108 is a top view of an indexing collar assembly, having anindexing collar, according to one embodiment.

FIG. 109 is a side view of the indexing collar assembly of FIG. 108.

FIG. 110 is an end cross section view of the indexing collar of FIG.108.

FIG. 111 is an end view of the indexing collar of FIG. 108.

FIG. 112 is a schematic view of a passage of the indexing collar of FIG.108.

FIG. 113 is a top view of the indexing collar of FIG. 108.

FIG. 114 is a side view of the indexing collar of FIG. 108.

FIG. 115 is a side cross section view of the indexing collar of FIG.108.

FIG. 116 is a bottom view of the indexing collar of FIG. 108.

FIG. 117 illustrates a portion of the indexing collar of FIG. 108.

FIG. 118 is a bottom perspective view of the indexing collar of FIG.108.

FIG. 119 is a top perspective view of the indexing collar of FIG. 108.

FIG. 120 is a side view of an oval or oblong shaped dilator, accordingto one embodiment.

FIG. 121 is an end view of the dilator of FIG. 120.

FIG. 122 is another side view of the dilator of FIG. 120.

FIG. 123 is a side view of an access device assembly in a low profileconfiguration, according to one embodiment.

FIG. 124 is a front view of the access device assembly of FIG. 123.

FIG. 125 is a top view of the access device assembly of FIG. 123 in anexpanded configuration.

FIG. 126 is a front view of the access device assembly of FIG. 123 in anexpanded configuration.

FIG. 127 is a cross section view of a lock coupling location of theaccess device assembly of FIG. 123, taken along section plane 127-127.

FIG. 128 is a cross section view of a skirt coupling location of theaccess device assembly of FIG. 123, taken along section plane 128-128.

FIG. 129 is a cross section view of a proximal portion coupling locationof the access device assembly of FIG. 123, taken along section plane129-129.

FIG. 130 is a top view of a proximal portion of the access device ofFIG. 123.

FIG. 131 is a front view of the proximal portion of the access device ofFIG. 123.

FIG. 132 is a side view of the proximal portion of the access device ofFIG. 123.

FIG. 133 illustrates a first locking skirt portion of a distal portionof the access device of FIG. 123.

FIG. 134 illustrates a second locking skirt portion of the distalportion of the access device of FIG. 123.

FIG. 135 is a side view of a locking element of the access device ofFIG. 123.

FIG. 136 is a side view of a locking element of the access device ofFIG. 123.

FIG. 137 is a side view of a locking element of the access device ofFIG. 123.

FIG. 138 illustrates a friction washer of the access device of FIG. 123.

FIG. 139 is a side view of an access device assembly in a low profileconfiguration, according to another embodiment.

FIG. 140 is a front view of the access device assembly of FIG. 139.

FIG. 141 is a top view of the access device assembly of FIG. 139 in anexpanded configuration.

FIG. 142 is a front view of the access device assembly of FIG. 139 in anexpanded configuration.

FIG. 143 is a cross section view of a lock coupling location of theaccess device assembly of FIG. 139, taken along section plane 143-143.

FIG. 144 is a cross section view of a skirt coupling location of theaccess device assembly of FIG. 139, taken along section plane 144-144.

FIG. 145 is a cross section view of a proximal portion coupling locationof the access device assembly of FIG. 139, taken along section plane145-145.

FIG. 146 is a top view of a proximal portion of the access device ofFIG. 139.

FIG. 147 is a front view of the proximal portion of the access device ofFIG. 139.

FIG. 148 is a side view of the proximal portion of the access device ofFIG. 139.

FIG. 149 illustrates a first locking skirt portion of a distal portionof the access device of FIG. 139.

FIG. 150 illustrates a second locking skirt portion of the distalportion of the access device of FIG. 139.

FIG. 151 is an exploded view of a portion of an apparatus constructed inaccordance with one embodiment.

FIG. 152 is a sectional view of the apparatus of FIG. 151.

FIG. 153 is an enlarged sectional view of a portion of the apparatus ofFIG. 151.

FIG. 154 is a plan view of a spring member of the apparatus of FIG. 151.

FIG. 155 is a side view of the spring member of FIG. 154.

FIG. 156 is an enlarged partial cross-sectional view of an apparatusconstructed in accordance with another embodiment.

FIG. 157 is a cross-sectional view of a cap screw constructed inaccordance with another embodiment.

FIG. 158 is a bottom view of the cap screw of FIG. 157.

FIG. 159 is a perspective view of the cap screw of FIG. 157.

FIG. 160 is a partial cross-sectional view of an apparatus constructedin accordance with the embodiment of FIG. 157.

FIG. 161 is a cross-sectional view of a housing of an apparatusconstructed in accordance with another embodiment.

FIG. 162 is an enlarged partial cross-sectional view of the housing ofFIG. 161

FIG. 163 is an enlarged partial cross-sectional view of a housing of anapparatus constructed in accordance with another embodiment.

FIG. 164 is an enlarged partial cross-sectional view of a housing of anapparatus constructed in accordance with another embodiment.

FIG. 165 is an enlarged partial cross-sectional view of a housing of anapparatus constructed in accordance with another embodiment.

FIG. 166 is an enlarged partial cross-sectional view of a housing of anapparatus constructed in accordance with another embodiment.

FIG. 167 is a front view of an apparatus constructed in accordance withanother embodiment.

FIG. 168 is a side view of the apparatus of FIG. 167.

FIG. 169 is a partial cross-sectional view of the apparatus of FIGS. 167and 168.

FIG. 170 is an exploded view of the apparatus of FIGS. 167-169.

FIG. 171 is a cross-sectional view of an apparatus constructed accordingto another embodiment.

FIG. 172 is an enlarged cross-sectional view showing the contact betweenthe housing and the fastener of the apparatus of FIG. 171.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As should be understood in view of the following detailed description,this application is primarily directed to, though not necessarilylimited to, apparatuses and methods for treating the spine of a patientthrough an access device. More particularly, the systems described belowprovide access to surgical locations at or near the spine and provide avariety of tools useful in performing treatment of the spine. Also, thesystems described herein enable a surgeon to perform a wide variety ofmethods as described herein. Some of the methods disclosed and enabledby the systems disclosed herein use an apparatus for retaining boneportions, such as vertebrae of a spinal column, in a desired spatialrelationship. Apparatuses for retaining bone portions are described inmore detail below in connection with FIGS. 26-37 and FIGS. 151-170.

I. Systems for Performing Procedures at a Surgical Location

Various embodiments of apparatuses and procedures described herein willbe discussed in terms of minimally invasive procedures and apparatuses,e.g., of endoscopic apparatuses and procedures. However, many aspects ofthe present invention may find use in conventional, open, and mini-openprocedures. As used herein, the term “proximal,” as is traditional,refers to the end portion of the apparatus that is closest to theoperator, while the term “distal” refers to the end portion that isfarthest from the operator.

FIG. 1 shows one embodiment of a surgical system 10 that can be used toperform a variety of methods or procedures. In one embodiment, asdiscussed more fully below, the patient P is placed in the proneposition on operating table T, taking care that the abdomen is notcompressed and physiological lordosis is preserved. The physician D isable to access the surgical site and perform the surgical procedure withthe components of the system 10, which will be described in greaterdetail herein. The system 10 may be supported, in part, by a mechanicalsupport arm A, such as the type generally disclosed in U.S. Pat. No.4,863,133, which is hereby incorporated by reference herein in itsentirety. One mechanical arm of this type is manufactured by LeonardMedical, Inc., 1464 Holcomb Road, Huntington Valley, Pa., 19006.

Visualization of the surgical site may be achieved in any suitablemanner, e.g., by use of a viewing element, such as an endoscope, acamera, loupes, a microscope, direct visualization, or any othersuitable viewing element, or a combination of the foregoing. In oneembodiment, the viewing element provides a video signal representingimages, such as images of the surgical site, to a monitor M. The viewingelement may be an endoscope and camera that captures images to bedisplayed on the monitor M whereby the physician D is able to view thesurgical site as the procedure is being performed. The endoscope andcamera will be described in greater detail herein.

The systems are described herein in connection with minimally invasivepostero-lateral spinal surgery. One such procedure is a two levelpostero-lateral fixation and fusion of the spine involving the L4, L5,and S1 vertebrae. In the drawings, the vertebrae will generally bedenoted by reference letter V. The usefulness of the apparatuses andprocedures is neither restricted to the postero-lateral approach nor tothe L4, L5, and S1 vertebrae. The apparatuses and procedures may be usedin other anatomical approaches and with other vertebra(e) within thecervical, thoracic, and lumbar regions of the spine. The procedures maybe directed toward surgery involving one or more vertebral levels. Someembodiments are useful for anterior and/or lateral procedures. Moreover,it is believed that embodiments of the invention are also particularlyuseful where any body structures must be accessed beneath the skin andmuscle tissue of the patient, and/or where it is desirable to providesufficient space and visibility in order to manipulate surgicalinstruments and treat the underlying body structures. For example,certain features or instrumentation described herein are particularlyuseful for minimally invasive procedures, e.g., arthroscopic procedures.As discussed more fully below, one embodiment of an apparatus describedherein provides an access device that has an expandable distal portion.In addition to providing greater access to a surgical site than would beprovided with device having a constant cross-section, the expandabledistal portion prevents or substantially prevents the access device, orinstruments extended therethrough to the surgical site, from dislodgingor popping out of the operative site.

In one embodiment, the system 10 includes an access device that providesan internal passage for surgical instruments to be inserted through theskin and muscle tissue of the patient P to the surgical site. The term“access device” is used in its ordinary sense to mean a device that canprovide access and is a broad term and it includes structures having anelongated dimension and defining a passage, e.g., a cannula or aconduit. The access device is configured to be inserted through the skinof the patient to provide access during a surgical procedure to asurgical location within a patient, e.g., a spinal location. The term“surgical location” is used in its ordinary sense (i.e. a location wherea surgical procedure is performed) and is a broad term and it includeslocations subject to or affected by a surgery. The term “spinallocation” is used in its ordinary sense (i.e. a location at or near aspine) and is a broad term and it includes locations adjacent to orassociated with a spine that may be sites for surgical spinalprocedures. The access device also can retract tissue to provide greateraccess to the surgical location.

The access device preferably has a wall portion defining a reducedprofile configuration for initial percutaneous insertion into thepatient. This wall portion may have any suitable arrangement. In oneembodiment, discussed in more detail below, the wall portion has agenerally tubular configuration that may be passed over a dilator thathas been inserted into the patient to atraumatically enlarge an openingsufficiently large to receive the access device therein.

The wall portion of the access device preferably can be subsequentlyexpanded to an enlarged configuration, by moving against the surroundingmuscle tissue to at least partially define an enlarged surgical space inwhich the surgical procedures will be performed. In a sense, it acts asits own dilator. The access device may also be thought of as aretractor, and may be referred to herein as such. Both the distal andproximal portion may be expanded, as discussed further below. However,the distal portion preferably expands to a greater extent than theproximal portion, because the surgical procedures are to be performed atthe surgical site, which is adjacent the distal portion when the accessdevice is inserted into the patient.

While in the reduced profile configuration, the access device preferablydefines a first unexpanded configuration. Thereafter, the access devicecan enlarge the surgical space defined thereby by engaging the tissuesurrounding the access device and displacing the tissue outwardly as theaccess device expands. The access device preferably is sufficientlyrigid to displace such tissue during the expansion thereof. The accessdevice may be resiliently biased to expand from the reduced profileconfiguration to the enlarged configuration. In addition, the accessdevice may also be manually expanded by an expander device with orwithout one or more surgical instruments inserted therein, as will bedescribed below. The surgical site preferably is at least partiallydefined by the expanded access device itself. During expansion, theaccess device can move from a first overlapping configuration to asecond overlapping configuration.

In some embodiments, the proximal and distal portions are separatecomponents that may be coupled together in a suitable fashion. Forexample, the distal end portion of the access device may be configuredfor relative movement with respect to the proximal end portion in orderto allow the physician to position the distal end portion at a desiredlocation. This relative movement also provides the advantage that theproximal portion of the access device nearest the physician D may remainsubstantially stable during such distal movement. In one embodiment, thedistal portion is a separate component that is pivotally or movablycoupled with the proximal portion. In another embodiment, the distalportion is flexible or resilient in order to permit such relativemovement.

A. Systems and Devices for Establishing Access

1. Access Devices

One embodiment of an access device is illustrated in FIGS. 2-6 anddesignated by reference number 20. In one embodiment, the access device20 includes a proximal wall portion 22 that has a tubular configuration,and a distal wall portion that has an expandable skirt portion 24. Theskirt portion 24 preferably is enlargeable from a reduced profileconfiguration having an initial dimension 26 (illustrated in FIG. 2) andcorresponding cross-sectional area, to an enlarged configuration havinga second dimension 28 (illustrated in FIG. 4) and correspondingcross-sectional area. In one embodiment, the skirt portion 24 is coupledwith the proximal wall portion 22 with a rivet 30, pin, or similarconnecting device to permit movement of the skirt portion 24 relative tothe proximal wall portion 22.

In the illustrated embodiment, the skirt portion 24 is manufactured froma resilient material, such as stainless steel. The skirt portion 24preferably is manufactured so that it normally assumes an expandedconfiguration as illustrated in FIG. 4. With reference to FIG. 3, theskirt portion 24 may assume an intermediate dimension 34 andcorresponding cross-sectional area, which is greater than the initialdimension 26 of the reduced profile configuration of FIG. 2, and smallerthan the dimension 28 of the enlarged configuration of FIG. 4. The skirtportion 24 may assume the intermediate configuration of FIG. 3 whendeployed in the patient in response to the force of the tissue acting onthe skirt portion 24. The intermediate dimension 34 can depend uponseveral factors, such as the rigidity of the skirt portion 24, thesurrounding tissue, and whether such surrounding tissue has relaxed ortightened during the course of the procedure. An outer sleeve 32(illustrated in dashed line in FIG. 2) may be provided. Preferably, theouter sleeve surrounds the access device 20 and maintains the skirtportion 24 in the reduced profile configuration prior to insertion intothe patient. The outer sleeve 32 may be made of plastic. Where provided,the outer sleeve 32 preferably is configured to be easily deployed. Forexample, a release device may be provided that releases or removes theouter sleeve 32 upon being operated by the user. In one embodiment, abraided polyester suture is embedded within the sleeve 32, alignedsubstantially along the longitudinal axis thereof. In use, when thesuture is withdrawn, the outer sleeve 32 is torn, allowing the accessdevice 20 to resiliently expand from the reduced profile configurationof FIG. 2 to the expanded configurations of FIGS. 3-4. While in thereduced profile configuration of FIG. 2, the skirt portion 24 defines afirst overlapping configuration 33, as illustrated by the dashed line.As the skirt portion 24 resiliently expands, the skirt portion 24assumes the expanded configuration, as illustrated in FIGS. 3-4.

The skirt portion 24 preferably is sufficiently rigid that it is capableof displacing the tissue surrounding the skirt portion 24 as it expands.Depending upon the resistance exerted by surrounding tissue, the skirtportion 24 preferably is sufficiently rigid to provide some resistanceagainst the tissue to remain in the configurations of FIGS. 3-4.Moreover, the expanded configuration of the skirt portion 24 is at leastpartially supported by the body tissue of the patient. The rigidity ofthe skirt portion 24 and the greater expansion at the distal portionpreferably creates a stable configuration that is at least temporarilystationary in the patient. This arrangement preferably frees thephysician from the need to actively support the access device 20, e.g.,prior to adding an endoscope mount platform 300 and a support arm 400(see FIGS. 21-22).

One embodiment of the skirt portion 24 of the access device 20 isillustrated in an initial flattened configuration in FIG. 5. The skirtportion 24 may be manufactured from a sheet of stainless steel having athickness of about 0.007 inches (0.178 mm). In various embodiments, thedimension 28 of the skirt portion 24 is about equal to or greater than50 mm, is about equal to or greater than 60 mm, is about equal to orgreater than 70 mm, is about equal to or greater than 80 mm, or is anyother suitable size, when the skirt portion 24 is in the enlargedconfiguration. In one embodiment, the dimension 28 is about 63 mm, whenthe skirt portion 24 is in the enlarged configuration. The unrestrictedshape of the skirt portion 24 is a circular shape in one embodiment andis an oblong shape in another embodiment. In another embodiment, theskirt portion 24 has an oval shape, wherein the dimension 28 defines alonger dimension of the skirt portion 24 and would be about 85 mm. Inanother embodiment, the skirt portion 24 has an oval shape and thedimension 28 defines a longer dimension of the skirt portion 24 of about63 mm. An increased thickness, e.g., about 0.010 inches (0.254 mm), maybe used in connection with skirt portions having a larger diameter, suchas about 65 mm. Other materials, such as nitinol or plastics havingsimilar properties, may also be useful.

As discussed above, the skirt portion 24 preferably is coupled with theproximal wall portion 22 with a pivotal connection, such as rivet 30. Apair of rivet holes 36 can be provided in the skirt portion 24 toreceive the rivet 30. The skirt portion 24 also has two free ends 38 and40 in one embodiment that are secured by a slidable connection, such asa second rivet 44 (not shown in FIG. 5, illustrated in FIGS. 2-4). Apair of complementary slots 46 and 48 preferably are defined in theskirt portion 24 adjacent the free ends 38 and 40. The rivet 44 ispermitted to move freely within the slots 46 and 48. This slot and rivetconfiguration allows the skirt portion 24 to move between the reducedprofile configuration of FIG. 2 and the enlarged or expandedconfigurations of FIGS. 3-4. The use of a pair of slots 46 and 48reduces the risk of the “button-holing” of the rivet 44, e.g., asituation in which the opening of the slot becomes distorted andenlarged such that the rivet may slide out of the slot, and causefailure of the device. The likelihood of such occurrence is reduced inskirt portion 24 because each of the slots 46 and 48 in the double slotconfiguration has a relatively shorter length than a single slotconfiguration. Being shorter, the slots 46, 48 are less likely to bedistorted to the extent that a rivet may slide out of position. Inaddition, the configuration of rivet 44 and slots 46 and 48 permits asmoother operation of enlarging and reducing the skirt portion 24, andallows the skirt portion 24 to expand to span three or more vertebrae,e.g., L4, L5, and S1. This arrangement enables multi-level procedures,such as multilevel fixation procedures alone or in combination with avariety of other procedures, as discussed below. Other embodimentsinclude a single slot rather than the slots 46, 48, or more than twoslots.

An additional feature of the skirt portion 24 is the provision of ashallow concave profile 50 defined along the distal edge of the skirtportion 24, which allows for improved placement of the skirt portion 24with respect to the body structures and the surgical instruments definedherein. In one embodiment, a pair of small scalloped or notched portions56 and 58 are provided, as illustrated in FIG. 5. When the skirt portion24 is assembled, the notched portions 56 and 58 are generally acrossfrom each other. When the skirt portion 24 is applied to a patient, thenotched portions 56, 58 are oriented in the ceph-caudal direction(indicated by a dashed line 60 in FIG. 4). In this arrangement,instruments and implants, such as an elongated member 650 used in afixation procedure (described in detail below), may extend beyond thearea enclosed by the skirt portion 24 without moving or raising theskirt portion 24, e.g., by allowing the elongated member 650 (or otherimplant or instrument) to pass under the skirt portion 24. The notchedportions 56, 58 also enable the elongated member 650 (or other implantor instrument) to extend beyond the portion of the surgical spacedefined within the outline of the distal end of the skirt portion 24.The notched portions 56, 58 are optional, as illustrated in connectionwith another embodiment of an access device 54, illustrated in FIG. 6,and may be eliminated if, for example, the physician deems the notchesto be unnecessary for the procedures to be performed. For example, insome fixation procedures such extended access is not needed, asdiscussed more fully below. As illustrated in FIG. 4, the skirt portion24 may be expanded to a substantially conical configuration having asubstantially circular or elliptical profile.

Furthermore, it is contemplated that the skirt portion 24 of the accessdevice 20 can include a stop that retains the skirt portion in anexpanded configuration, as shown in U.S. patent application Ser. No.10/361,887, filed Feb. 10, 2003, now U.S. Application Patent PublicationNo. US2003/153927 A1, which is hereby incorporated by reference in itsentirety herein.

In another embodiment, features may be provided on the skirt portion 24which facilitate the bending of the skirt portion at several locationsto provide a pre-formed enlarged configuration. For example, anotherembodiment of an access device 70, illustrated in FIGS. 7-9, provides askirt portion 74 that has four sections 76 a, 76 b, 76 c, 76 d having areduced thickness. For a skirt portion 74 having a thickness 78 of about0.007 inches (0.178 mm), reduced thickness sections 76 a, 76 b, 76 c, 76d may have a thickness 80 of about 0.002-0.004 inches (0.102 mm) (FIG.8). The reduced thickness sections 76 a, 76 b, 76 c, 76 d may have awidth 82 of about 1-5 mm. The thickness 78 of the skirt portion 74 maybe reduced by milling or grinding, as is known in the art. When theskirt portion 74 is opened, it moves toward a substantially rectangularconfiguration, as shown in FIG. 9, subject to the resisting forces ofthe body tissue. In another embodiment (not shown), a skirt portion maybe provided with two reduced thickness sections (rather than the fourreduced thickness sections of skirt 74) which would produce an oblong,substantially “football”-shaped access area.

FIGS. 10-12 show another embodiment of an access device 80. The accessdevice 80 has a skirt portion 84 with a plurality of perforations 86.The perforations 86 advantageously increase the flexibility at selectedlocations. The size and number of perforations 86 may vary dependingupon the desired flexibility and durability. In another embodiment, theskirt portion 84 may be scored or otherwise provided with a groove orrib in order to facilitate the bending of the skirt portion at thedesired location.

FIG. 13 illustrates another embodiment of an access device that has askirt portion 94 having one slot 96 and an aperture 98. A rivet (notshown) is stationary with respect to the aperture 98 and slides withinthe slot 96. FIG. 14 illustrates another embodiment of an access devicethat has a skirt portion 104 that includes an aperture 108. Theapertures 108 receives a rivet (not shown) that slides within elongatedslot 106.

Another embodiment of an access device comprises an elongate bodydefining a passage and having a proximal end and a distal end. Theelongate body has a proximal portion and a distal portion. The proximalportion has an oblong or generally oval shaped cross section in oneembodiment. The term “oblong” is used in its ordinary sense (i.e.,having an elongated form) and is a broad term and it includes astructure having a dimension, especially one of two perpendiculardimensions, such as, for example, width or length, that is greater thananother and includes shapes such as rectangles, ovals, ellipses,triangles, diamonds, trapezoids, parabolas, and other elongated shapeshaving straight or curved sides. The term “oval” is used in its ordinarysense (i.e., egg like or elliptical) and is a broad term and includesoblong shapes having curved portions.

The proximal portion comprises an oblong, generally oval shaped crosssection over the elongated portion. It will be apparent to those ofskill in the art that the cross section can be of any suitable oblongshape. The proximal portion can be any desired size. The proximalportion can have a cross-sectional area that varies from one end of theproximal portion to another end. For example, the cross-sectional areaof the proximal portion can increase or decrease along the length of theproximal portion. Alternatively, the proximal portion can have aconstant cross section over its length. Preferably, the proximal portionis sized to provide sufficient space for inserting multiple surgicalinstruments through the elongate body to the surgical location. Thedistal portion preferably is expandable and may comprise first andsecond overlapping skirt members. The degree of expansion of the distalportion is determined by an amount of overlap between the first skirtmember and the second skirt member in one embodiment.

The elongate body of the access device has a first location distal of asecond location. The elongate body preferably is capable of having aconfiguration when inserted within the patient wherein thecross-sectional area of the passage at the first location is greaterthan the cross-sectional area of the passage at the second location. Thepassage preferably is capable of having an oblong shaped cross sectionbetween the second location and the proximal end. In some embodimentsthe passage preferably is capable of having a generally elliptical crosssection between the second location and the proximal end. Additionally,the passage preferably is capable of having a non-circular cross sectionbetween the second location and the proximal end. Additionally, in someembodiments, the cross section of the passage can be symmetrical about afirst axis and a second axis, the first axis being generally normal tothe second axis. Other embodiments having an oblong cross-section arediscussed below in connection with FIGS. 67-73B.

Further details and features pertaining to access devices and systemsare described in U.S. Pat. No. 6,652,553, application Ser. No.10/361,887, filed Feb. 10, 2003, application Ser. No. 10/280,489, filedOct. 25, 2002, and application Ser. No. 10/678,744 filed Oct. 2, 2003,which are incorporated by reference in their entireties herein.

2. Dilators and Expander Devices

According to one embodiment of a procedure, an early stage involvesdetermining a point in the skin of the patient at which to insert theaccess device 20. The access point preferably corresponds to aposterior-lateral aspect of the spine. Manual palpation andAnterior-Posterior (AP) fluoroscopy may be used to determine preferredor optimal locations for forming an incision in the skin of the patient.In one application, the access device 20 preferably is placed midway (inthe cephcaudal direction) between the L4 through S1 vertebrae, centrallyabout 4-7 cm from the midline of the spine.

After the above-described location is determined, an incision is made atthe location. A guide wire (not shown) is introduced under fluoroscopicguidance through the skin, fascia, and muscle to the approximatesurgical site. A series of dilators is used to sequentially expand theincision to the desired width, about 23 mm in one procedure, preferablyminimizing damage to the structure of surrounding tissue and muscles. Afirst dilator can be placed over the guide wire to expand the opening.The guide wire may then be removed. A second dilator, slightly largerthan the first dilator, is placed over the first dilator to expand theopening further. Once the second dilator is in place, the first dilatormay be removed. This process of (1) introducing a next-larger-sizeddilator coaxially over the previous dilator and (2) optionally removingthe previous dilator(s) when the next-larger-sized dilator is in placecontinues until an opening of the desired size is created in the skin,muscle, and subcutaneous tissue. According to one application, thedesired opening size is about 23 mm. (Other dimensions of the opening,e.g., about 20 mm, about 27 mm, about 30 mm, etc., are also useful withthis apparatus in connection with spinal surgery, and still otherdimensions are contemplated.)

FIG. 15 shows that following placement of a dilator 120, which is thelargest dilator in the above-described dilation process, the accessdevice 20 is introduced in its reduced profile configuration andpositioned over the dilator 120. The dilator 120 is subsequently removedfrom the patient, and the access device 20 remains in position.

Once positioned in the patient, the access device 20 may be enlarged toprovide a passage for the insertion of various surgical instruments andto provide an enlarged space for performing the procedures describedherein. As described above, the access device may achieve theenlargement in several ways. In one embodiment, a distal portion of theaccess device may be enlarged, and a proximal portion may maintain aconstant diameter. The relative lengths of the proximal portion 22 andthe skirt portion 24 may be adjusted to vary the overall expansion ofthe access device 20. Alternatively, such expansion may extend along theentire length of the access device 20. In one application, the accessdevice 20 may be expanded by removing a suture 35 and tearing the outersleeve 32 surrounding the access device 20, and subsequently allowingthe skirt portion 24 to resiliently expand towards its fully expandedconfiguration as (illustrated in FIG. 4) to create an enlarged surgicalspace from the L4 to the S1 vertebrae. The resisting force exerted onthe skirt portion 24 may result in the skirt portion 24 assuming theintermediate configuration illustrated in FIG. 3. Under manycircumstances, the space created by the skirt portion 24 in theintermediate configuration is a sufficiently large working space toperform the procedure described herein. Once the skirt portion 24 hasexpanded, the rigidity and resilient characteristics of the skirtportion 24 preferably allow the access device 20 to resist closing tothe reduced profile configuration of FIG. 2 and to at least temporarilyresist being expelled from the incision. These characteristics create astable configuration for the access device 20 to remain in position inthe body, supported by the surrounding tissue. It is understood thatadditional support may be needed, especially if an endoscope is added.

According to one embodiment of a procedure, the access device 20 may befurther enlarged at the skirt portion 24 using an expander apparatus tocreate a surgical access space. An expander apparatus useful forenlarging the access device has a reduced profile configuration and anenlarged configuration. The expander apparatus is inserted into theaccess device in the reduced profile configuration, and subsequentlyexpanded to the enlarged configuration. The expansion of the expanderapparatus also causes the access device to be expanded to the enlargedconfiguration. In some embodiments, the expander apparatus may increasethe diameter of the access device along substantially its entire lengthin a generally conical configuration. In other embodiments, the expanderapparatus expands only a distal portion of the access device, allowing aproximal portion to maintain a relatively constant diameter.

In addition to expanding the access device, in some embodiments theexpander apparatus may also be used to position the distal portion ofthe access device at the desired location for the surgical procedure.The expander can engage an interior wall of the access device to movethe access device to the desired location. For embodiments in which thedistal portion of the access device is relatively movable with respectto the proximal portion, the expander apparatus is useful to positionthe distal portion without substantially disturbing the proximalportion.

In some procedures, an expander apparatus is used to further expand theskirt portion 24 towards the enlarged configuration (illustrated in FIG.4). The expander apparatus is inserted into the access device, andtypically has two or more members that are movable to engage theinterior wall of the skirt portion 24 and apply a force sufficient tofurther expand the skirt portion 24. FIGS. 16 and 17 show one embodimentof an expander apparatus 200 that has a first component 202 and a secondcomponent 204. The first component 202 and the second component 204 ofthe expander apparatus 200 are arranged in a tongs-like configurationand are pivotable about a pin 206. The first and second components 202and 204 can be constructed of steel having a thickness of about 9.7 mm.Each of the first and second components 202 and 204 has a proximalhandle portion 208 and a distal expander portion 210. Each proximalhandle portion 208 has a finger grip 212 that may extend transverselyfrom an axis, e.g., a longitudinal axis 214, of the apparatus 200. Theproximal handle portion 208 may further include a stop element, such asflange 216, that extends transversely from the longitudinal axis 214.The flange 216 preferably is dimensioned to engage the proximal end 25of the access device 20 when the apparatus 200 is inserted apredetermined depth. This arrangement provides a visual and tactileindication of the proper depth for inserting the expander apparatus 200.In one embodiment, a dimension 218 from the flange 216 to the distal tip220 is about 106 mm. The dimension 218 is determined by the length ofthe access device 20, which in turn is a function of the depth of thebody structures beneath the skin surface at which the surgical procedureis to be performed. The distal portions 210 are each provided with anouter surface 222 for engaging the inside wall of the skirt portion 24.The outer surface 222 is a frusto-conical surface in one embodiment. Theexpander apparatus 200 has an unexpanded distal width 224 at the distaltip 220 that is about 18.5 mm in one embodiment.

In use, the finger grips 212 are approximated towards one another, asindicated by arrows A in FIG. 17, which causes the distal portions 210to move to the enlarged configuration, as indicated by arrows B. Thecomponents 202 and 204 are also provided with a cooperating tab 226 andshoulder portion 228 which are configured for mutual engagement when thedistal portions 210 are in the expanded configuration. In theillustrated embodiment, the expander apparatus 200 has an expandeddistal width 230 that extends between the distal portions 210. Theexpanded distal width 230 can be about 65 mm or less, about as large as83 mm or less, or any other suitable width. The tab 226 and shoulderportion 228 together limit the expansion of the expander apparatus 200to prevent expansion of the skirt portion 24 of the access device 20beyond its designed dimension, and to minimize trauma to the underlyingtissue. Further features related to the expander apparatus are describedin U.S. Pat. No. 6,652,553, issued Nov. 25, 2003, which is incorporatedby reference in its entirety herein.

When the access device 20 is inserted into the patient and the outersleeve 32 is removed, the skirt portion 24 expands to a point where theoutward resilient expansion of the skirt portion 24 is balanced by theforce of the surrounding tissue. The surgical space defined by theaccess device 20 may be sufficient to perform any of a number ofsurgical procedures or combination of surgical procedures describedherein. However, if it is desired to expand the access device 20further, the expander apparatus 200, or a similar device, may beinserted into the access device 20 in the reduced profile configurationuntil the shoulder portions 216 are in approximation with the proximalend 25 of the skirt portion 24 of the access device 20, as shown in FIG.18.

FIG. 18 shows the expander apparatus 200 inserted in the access device20 in the reduced profiled configuration. Expansion of the expanderapparatus 200 is achieved by approximating the handle portions 212 (notshown in FIG. 18), which causes the distal portions 210 of the expanderapparatus 200 to move to a spaced apart configuration. As the distalportions 210 move apart and contact the inner wall of the skirt portion24, the rivet 44 is allowed to slide within the slots 46 and 48 of theskirt portion 24, thus permitting the skirt portion 24 to expand. Whenthe distal portions 210 reach the maximum expansion of the skirt portion24 (illustrated by a dashed line in FIG. 19), the tab 226 and shoulderportion 228 of the expander apparatus 200 come into engagement toprevent further expansion of the tongs-like portions (as illustrated inFIG. 17). Alternatively, the access device 20 may be expanded withanother device that can selectively have a reduced profile configurationand an expanded configuration, e.g., a balloon or similar device.

An optional step in the procedure is to adjust the location of thedistal portion of the access device 20 relative to the body structuresto be operated on. For example, the expander apparatus 200 may also beused to engage the inner wall of the skirt portion 24 of the accessdevice 20 in order to move the skirt portion 24 of the access device 20to the desired location. For an embodiment in which the skirt portion 24of the access device 20 is relatively movable relative to the proximalportion, e.g. by use of the rivet 30, the expander apparatus 200 isuseful to position the skirt portion 24 without substantially disturbingthe proximal portion 22 or the tissues closer to the skin surface of thepatient. As will be described below, the ability to move the distal endportion, e.g., the skirt portion 24, without disturbing the proximalportion is especially beneficial when an additional apparatus is coupledwith the proximal portion of the access device, as described below.

B. Systems and Devices for Stabilization and Visualization

Some procedures can be conducted through the access device 20 withoutany additional peripheral components being connected thereto. In otherprocedures it may be beneficial to provide at least one of a supportdevice and a viewing element. As discussed more fully below, supportdevices can be advantageously employed to provide support to peripheralequipment and to surgical tools of various types. Various embodiments ofsupport devices and viewing elements are discussed herein below.

1. Support Devices

One type of support device that can be coupled with the access device 20is a device that supports a viewing element. In one embodiment, anendoscope mount platform 300 and indexing arm 400 support an endoscope500 on the proximal end 25 of the access device 20 for remotely viewingthe surgical procedure, as illustrated in FIGS. 20-23. The endoscopemount platform 300 may also provide several other functions during thesurgical procedure. The endoscope mount platform 300 preferably includesa base 302 that extends laterally from a central opening 304 in agenerally ring-shaped configuration. In one application, the physicianviews the procedure primarily by observing a monitor, when insertingsurgical instruments into the central opening 304. The base 302advantageously enables the physician by providing a visual indicator (inthat it may be observable in the physician's peripheral vision) as wellas tactile feedback as instruments are lowered towards the centralopening 304 and into the access device 20.

The endoscope mount platform 300 preferably has a guide portion 306 at alocation off-set from the central opening 304 that extends substantiallyparallel to a longitudinal axis 308. The base 302 can be molded as onepiece with the guide portion 306. The base 302 and guide portion 306 maybe constructed with a suitable polymer, such as, for example,polyetheretherketone (PEEK).

The guide portion 306 includes a first upright member 310 that extendsupward from the base 302 and a second upright member 312 that extendsupward from the base 302. In one embodiment, the upright members 310,312 each have a respective vertical groove 314 and 315 that can slidablyreceive an endoscopic mount assembly 318.

The endoscope 500 (not shown in FIG. 20) can be movably mounted to theendoscope mount platform 300 with the endoscope mount assembly 318 inone embodiment. The endoscope mount assembly 318 includes an endoscopemount 320 and a saddle unit 322. The saddle unit 322 is slidably mountedwithin the grooves 314 and 315 in the upright members 310 and 312. Theendoscope mount 320 receives the endoscope 500 through a bore 326 whichpasses through the endoscope mount 320. Part of the endoscope 500 mayextend through the access device 20 substantially parallel tolongitudinal axis 308 into the patient's body 130, as shown in FIG. 25.

The endoscope mount 320 is removably positioned in a recess 328 definedin the substantially “U”-shaped saddle unit 322. In one embodiment, thesaddle unit 322 is selectively movable in a direction parallel to thelongitudinal axis 308 in order to position the endoscope 500 at thedesired height within the access device 20. The movement of theendoscope 500 by way of the saddle unit 322 also advantageously enablesthe physician to increase visualization of a particular portion of thesurgical space defined by the access device, e.g., by way of a zoomfeature, as required for a given procedure or a step of a procedure.

In one embodiment, an elevation adjustment mechanism 340, which may be ascrew mechanism, is positioned on the base 302 between the uprightmembers 310 and 312. The elevation adjustment mechanism 340 can be usedto selectively move a viewing element, e.g., the endoscope 500 by way ofthe saddle unit 322. In one embodiment, the elevation adjustmentmechanism 340 comprises a thumb wheel 342 and a spindle 344. The thumbwheel 343 is rotatably mounted in a bore in the base 302. The thumbwheel 342 has an external thread 346 received in a cooperating thread inthe base 302. The spindle 344 is mounted for movement substantiallyparallel to the central axis 308. The spindle 344 preferably has a firstend received in a rectangular opening in the saddle unit 322, whichinhibits rotational movement of the spindle 344. The second end of thespindle 344 has an external thread that cooperates with an internalthread formed in a bore within the thumb wheel 342. Rotation of thethumb wheel 342 relative to the spindle 344 causes relative axialmovement of the spindle unit 344 along with the saddle unit 322. Furtherdetails and features related to endoscope mount platforms are describedin U.S. Pat. No. 6,361,488, issued Mar. 26, 2002; U.S. Pat. No.6,530,880, issued Mar. 11, 2003, and U.S. patent application Ser. No.09/940,402, filed Aug. 27, 2001, published as Publication No.2003/0040656 on Feb. 27, 2003, which are incorporated by reference intheir entireties herein.

FIGS. 21-23 show that the endoscope mount platform 300 is mountable tothe support arm 400 in one embodiment. The support arm 400, in turn,preferably is mountable to a mechanical support, such as mechanicalsupport arm A, discussed above in connection with FIG. 1. The supportarm 400 preferably rests on, or is otherwise coupled with, the proximalend 25 of the access device 20. In one embodiment, the support arm 400is coupled with an indexing collar 420, which is configured to bereceived in the central opening 304 of the base 302 of endoscope mountplatform 300. The indexing collar 420 is substantially toroidal insection and has an outer peripheral wall surface 422, an inner wallsurface 424, and a wall thickness 426 that is the distance between thewall surfaces 422, 424. The indexing collar 420 further includes aflange 428, which supports the indexing collar 420 on the support arm400.

In one embodiment, a plurality of collars 420 may be provided to makethe surgical system 10 modular in that different access devices 20 maybe used with a single endoscope mount platform 300. For example, accessdevices 20 of different dimensions may be supported by providingindexing collars 420 to accommodate each access device size while usinga single endoscope mount platform 300. The central opening 304 of theendoscope mount platform 300 can have a constant dimension, e.g., adiameter of about 32.6 mm. An appropriate indexing collar 420 isselected, e.g., one that is appropriately sized to support a selectedaccess device 20. Thus, the outer wall 422 and the outer diameter 430are unchanged between different indexing collars 420, although the innerwall 424 and the inner diameter 432 vary to accommodate differentlysized access devices 20.

The indexing collar 420 can be positioned at or rested on the proximalportion of the access device 20 to allow angular movement of theendoscope mount platform 300 with respect thereto about the longitudinalaxis 308 (as indicated by an arrow C in FIG. 21). The outer wall 422 ofthe index collar 420 includes a plurality of hemispherical recesses 450that can receive one or more ball plungers 350 on the endoscope mountplatform 300 (indicated in dashed line). This arrangement permits theendoscope mount platform 300, along with the endoscope 500, to be fixedin a plurality of discrete angular positions. Further details andfeatures related to support arms and indexing collars are described inU.S. Pat. No. 6,361,488, issued Mar. 26, 2002, U.S. Pat. No. 6,530,880issued Mar. 11, 2003, and application Ser. No. 09/940,402 filed Aug. 27,2001, published as Publication No. 2003/0040656 on Feb. 27, 2003, whichare incorporated by reference in their entireties herein.

2. Viewing Elements

As discussed above, a variety of viewing elements and visualizationtechniques are embodied in variations of the surgical system 10. Oneviewing element that is provided in one embodiment is an endoscope.

FIG. 24 shows one embodiment of the endoscope 500 that has an elongatedconfiguration that extends into the access device 20 in order to enableviewing of the surgical site. In particular, the endoscope 500 has anelongated rod portion 502 and a body portion 504. The rod portion 502extends generally perpendicularly from the body portion 504. In oneembodiment, the rod portion 502 of endoscope 500 has a diameter of about4 mm and a length of about 106 mm. Body portion 504 may define a tubularportion 506 configured to be slidably received in the bore 326 ofendoscope mount 320 as indicated by an arrow D. The slidable mounting ofthe endoscope 500 on the endoscope mount platform 300 permits theendoscope 500 to adjust to access device configurations that havedifferent diameters. Additional mobility of the endoscope 500 in viewingthe surgical site may be provided by rotating the endoscope mountplatform 300 about the central axis 308 (as indicated by arrow C in FIG.21).

The rod portion 502 supports an optical portion (not shown) at a distalend 508 thereof. In one embodiment, the rod portion 502 defines a fieldof view of about 105 degrees and a direction of view 511 of about 25-30degrees. An eyepiece 512 preferably is positioned at an end portion ofthe body portion 504. A suitable camera (not shown) preferably isattached to the endoscope 500 adjacent the eyepiece 512 with a standardcoupler unit. A light post 510 can supply illumination to the surgicalsite at the distal end portion 508. A preferred camera for use in thesystem and procedures described herein is a three chip unit thatprovides greater resolution to the viewed image than a single chipdevice.

C. Apparatuses and Methods for Performing Spinal Procedures

The surgical assembly 10 described above can be deployed to perform awide variety of surgical procedures on the spine. In many cases, theprocedures are facilitated by inserting the access device andconfiguring it to provide greater access to a surgical location, asdiscussed above and by coupling the support arm 400 and the endoscopemount platform 300 with the proximal portion, e.g., on the proximal end25, of the access device 20 (FIGS. 1 and 22). As discussed above,visualization of the surgical location is enhanced by mounting a viewingelement, such as the endoscope 500, on the endoscope mount platform 300.Having established increased access to and visualization of the surgicallocation, a number of procedures may be effectively performed.

Generally, the procedures involve inserting one or more surgicalinstruments into the access device 20 to manipulate or act on the bodystructures that are located at least partially within the operativespace defined by the expanded portion of the access device 20. FIG. 25shows that in one method, the skirt portion 24 of access device 20 atleast partially defines a surgical site or operative space 90 in whichthe surgical procedures described herein may be performed. Dependingupon the overlap of the skirt portion, the skirt portion may define asurface which is continuous about the perimeter or which isdiscontinuous, having one or more gaps where the material of the skirtportion does not overlap.

One procedure performable through the access device 20, described ingreater detail below, is a two-level spinal fusion and fixation.Surgical instruments inserted into the access device may be used fordebridement and decortication. In particular, the soft tissue, such asfat and muscle, covering the vertebrae may be removed in order to allowthe physician to visually identify the various “landmarks,” or vertebralstructures, which enable the physician to determine the location forattaching a fastener or an apparatus to vertebrae or to perform otherprocedures, as will be described herein. Any suitable fastener orapparatus may be attached to the vertebrae, including a fastener 600,and an apparatus 8010, discussed below, and additional fasteners andapparatuses incorporated by reference herein. Enabling visualidentification of the vertebral structures enables the physician toperform the procedure while viewing the surgical area through theendoscope, microscope, loupes, or other viewing element, or in aconventional, open manner.

Tissue debridement and decortication of bone are completed using one ormore of a debrider blade, a bipolar sheath, a high speed burr, and anyother conventional manual instrument. The debrider blades are used toexcise, remove and aspirate the soft tissue. The bipolar sheath is usedto achieve hemostasis through spot and bulk tissue coagulation.Additional features of debrider blades and bipolar sheaths are describedin U.S. Pat. No. 6,193,715, assigned to Medical Scientific, Inc., whichis incorporated by reference in its entirety herein. The high speed burrand conventional manual instruments are also used to continue to exposethe structure of the vertebrae.

1. Fixation Systems and Devices

Having increased visualization of the pertinent anatomical structure,various procedures may be carried out on the structures. In oneprocedure, one or more fasteners are attached to adjacent vertebrae V.As discussed in more detail below, the fasteners can be used to providetemporary or permanent fixation and to provide dynamic stabilization ofthe vertebrae V. These procedures may combined with other procedures,such as procedures employing other types of implant, e.g., proceduresemploying fusion devices, prosthetic disc components, or other suitableimplants. In some procedures, fasteners are attached to the vertebraebefore or after fusion devices are inserted between the vertebrae V.Fusion systems and devices are discussed further below.

In one application, the desired location and orientation of the fasteneris determined before the fastener is applied to the vertebra. Thedesired location and orientation of the fastener may be determined inany suitable manner. For example, the pedicle entry point of the L5vertebrae may be located by identifying visual landmarks alone or incombination with lateral and A/P fluoroscopy, as is known in the art.With continued reference to FIG. 25, an entry point 92 into the vertebraV is prepared. In procedure, the entry point 92 may be prepared with anawl 550. The entry point 92 corresponds to the pedicle in one procedure.The entry point 92 may be prepared in any suitable manner, e.g.,employing a bone probe, a tap, and a sounder to create and verify theintegrity of the prepared vertebra. The sounder, as is known in the art,determines whether the hole that is made is surrounded by bone on allsides, and can be used to confirm that there has been no perforation ofthe pedicle wall.

After the hole in the pedicle beneath the entry point 92 is prepared, afastener may be advanced into the hole. Prior to advancing the fastener,or at any other point during the procedure, it may be desirable toadjust the location of the distal portion of the access device 20. Thedistal portion of the access device 20 may be adjusted by inserting theexpander apparatus 200 into the access device 20, expanding the distalportions 210, and contacting the inner wall of the skirt portion 24 tomove the skirt portion 24 to the desired location. This step may beperformed while the endoscope 500 is positioned within the access device20, and without substantially disturbing the location of the proximalportion of the access device 20 to which the endoscope mount platform300 may be attached.

FIGS. 26-27 illustrate one embodiment of a fastener 600 that isparticularly applicable in procedures involving fixation. Otherapparatuses that may be applicable in such procedures and in otherprocedure are described in connection with FIGS. 151-155 and areincorporated by reference herein below. The fastener 600 preferablyincludes a screw portion 602, a housing 604, a spacer member 606, abiasing member 608, and a clamping member, such as a cap screw 610. Thescrew portion 602 has a distal threaded portion 612 and a proximal,substantially spherical joint portion 614. The threaded portion 612 isinserted into the hole that extends away from the entry point 92 intothe vertebrae, as will be described below. The substantially sphericaljoint portion 614 is received in a substantially annular, partlyspherical recess 616 in the housing 604 in a ball and socket jointrelationship (see also FIG. 29).

As illustrated in FIG. 27, the fastener 600 is assembled by insertingthe screw portion 602 into a bore in a passage 618 in the housing 604until the joint portion 614 engages the annular recess 616. The screwportion 602 is retained in the housing 604 by the spacer member 606 andby the biasing member 608. The biasing member 608 provides a biasingforce to drive the spacer member 606 into frictional engagement with thejoint portion 614 of the screw member 602 and the annular recess 616 ofthe housing 604. The biasing provided by the biasing member 602frictionally maintains the relative positions of the housing 604 withrespect to the screw portion 602. The biasing member 608 preferably isselected such that biasing force prevents unrestricted movement of thehousing 604 relative to the screw portion 602. However, in someembodiments the biasing force is insufficient to resist the applicationof force by a physician to move the housing 604 relative to the screwportion 602. In other words, this biasing force is strong enoughmaintain the housing 604 stationary relative to the screw portion 602,but this force may be overcome by the physician to reorient the housing604 with respect to the screw member 602, as will be described below.

In the illustrated embodiment, the biasing member 608 is a resilientring having a gap 620, which permits the biasing member 608 to radiallycontract and expand. FIG. 27( a) illustrates that the biasing member 608may have an arched shape, when viewed end-on. The arched shape of thespring member 608 provides the biasing force, as will be describedbelow. The spacer member 606 and the biasing member 608 are insertedinto the housing 604 by radially compressing the biasing member into anannular groove 622 in the spacer member 606. The spacer member 606 andthe biasing member 608 are slid into the passage 618 until the distalsurface of the spacer member 606 engages the joint portion 614 of thescrew portion 602, and the biasing member 608 expands radially into theannular groove 622 in the housing 604. The annular groove 622 in thehousing 604 has a dimension 623 that is smaller than the uncompressedheight of the arched shape of the biasing member 608. When the biasingmember 608 is inserted in the annular groove 620, the biasing member 608is flattened against its normal bias, thereby exerting the biasing forceto the spacer member 606. It is understood that similar biasing members,such as coiled springs, belleville washers, or the like may be used tosupply the biasing force described herein.

The spacer member 606 is provided with a longitudinal bore 626, whichprovides access to a hexagonal recess 628 in the proximal end of thejoint portion 614 of the screw member 602. The proximal portion of thehousing 604 includes a pair of upright members 630 and 631 that areseparated by substantially “U”-shaped grooves 632. A recess forreceiving elongated member 650 is defined by the pair of grooves 632between upright members 630 and 631. Elongated member 650 preferably isconfigured to be placed distally into the housing 604 in an orientationsubstantially transverse to the longitudinal axis of the housing 604, aswill be described below. The inner walls of he upright members 630 and631 are provided with threads 634 for attachment of the cap screw 610 bythreads 613 therein.

Additional features of the fastener 600 are also described in U.S.patent application Ser. No. 10/075,668, filed Feb. 13, 2002, publishedas U.S. Application Publication No. 2003/0153911A1 on Aug. 14, 2003, andapplication Ser. No. 10/087,489, filed Mar. 1, 2002, published as U.S.Application Publication No. 2003/0167058A1 on Sep. 4, 2003, which areincorporated by reference in their entireties herein.

According to one application, the fastener 600 is inserted into theaccess device 20 and guided to the prepared hole at the entry point 92in the vertebrae. The fastener 600 preferably is simultaneouslysupported and advanced into the hole so that the fastener 600 is securedin the in the hole beneath the entry point 92. In the illustratedembodiment the fastener 600 is supported and attached to the bone by anendoscopic screwdriver apparatus 660, illustrated in FIGS. 28-29. Thescrewdriver 660 includes a proximal handle portion 662 (illustrated indashed line), an elongated body portion 664, and a distal tool portion666.

The distal tool portion 666, as illustrated in greater detail in FIG. 29includes a substantially hexagonal outer periphery that is received inthe substantially hexagonal recess 628 in the joint portion 614 of thescrew member 602. A spring member at the distal tool portion 666releasably engages the hexagonal recess 628 of the screw member 602 tosupport the fastener 600 during insertion and tightening. In theillustrated embodiment, a spring member 672 is configured to engage theside wall of the recess 628. More particularly, a channel or a groove isprovided in the tip portion 666 for receiving the spring member 672. Thechannel or groove includes a medial longitudinal notch portion 676, aproximal, angled channel portion 678, and a distal substantiallytransverse channel portion 680. The spring member 672 is preferablymanufactured from stainless steel and has a medial portion 682, proximalportion 684, and a transverse distal portion 686. The medial portion 682is partially received in the longitudinal notch portion 676. Theproximal portion 684 preferably is angled with respect to the medialportion 682 and is fixedly received in the angled channel portion 678.The transverse distal portion 686 preferably is slidably received in thetransverse channel 680. The medial portion 682 of the spring member 672is partially exposed from the distal tip portion 666 and normally isbiased in a transverse outward direction with respect to thelongitudinal axis (indicated by arrow E), in order to supply bearingforce against the wall of the recess 628. Alternatively, the distal tipportion of the screwdriver may be magnetized in order to hold the screwportion 602. Similarly, the distal tip portion may include a ballbearing or similar member which is normally biased in a radially outwarddirection to engage the interior wall of the recess 628 to secure thefastener 600 to the screwdriver distal tip 666. Other means may beprovided for temporarily but securely coupling the fastener 600 with thescrewdriver distal tip 666.

The insertion of the fastener 600 into the prepared hole that extendsinto the vertebrae from the entry point 92 may be achieved by insertionof screwdriver 660 into access device 20 (indicated by arrow G). Thisprocedure may be visualized by the use of the endoscope 500 inconjunction with fluoroscopy, or by way of any other suitable viewingelement. The screw portion 602 is threadedly advanced by the endoscopicscrewdriver 660 into the prepared hole that extends beneath the entrypoint 92 (indicated by arrow H). The endoscopic screwdriver 660 issubsequently separated from the fastener 600, by applying a force in theproximal direction, and thereby releasing the distal tip portion 666from the hexagonal recess 628 (e.g., causing the transverse distalportion 686 of the spring member 672 to slide within the transverserecess 680 against the bias, indicated by arrow F), and removing thescrewdriver 660 from the access device 20. An alternative method may usea guidewire, which is fixed in the hole beneath the entry point 92, anda cannulated screw which has an internal lumen and is guided over theguidewire into the hole beneath the entry point 92. Where a guidewiresystem is used, the screwdriver also would be cannulated so that thescrewdriver would fit over the guidewire.

For a two-level fixation, it may be necessary to prepare several holesand attach several fasteners 600. Preferably, the access device 20 issized to provide simultaneous access to all vertebrae in which thesurgical procedure is being performed. In some cases, however,additional enlargement or repositioning of the distal portion of theaccess device 20 may be helpful in providing sufficient access to theouter vertebrae, e.g., the L4 and S1 vertebrae. In the illustratedembodiment, the expander apparatus 200 may be repeatedly inserted intothe access device 20 and expanded in order to further open or toposition the skirt portion 24. In one procedure, additional fastenersare inserted in the L4 and S1 vertebrae in a similar fashion as thefastener 600 inserted into the L5 vertebra as described above. (Whendiscussed individually or collectively, a fastener and/or its individualcomponents will be referred to by the reference number, e.g., fastener600, housing 604, and all fasteners 600. However, when several fastenersand/or their components are discussed in relation to one another, analphabetic subscript will be used, e.g., fastener 600 a is moved towardsfastener 600 b.)

In one application, after the fasteners 600 are advanced into thevertebrae, the housing portions 604 of the fasteners 600 aresubstantially aligned such that their upright portions 630 and 631 faceupward, and the notches 632 are substantially aligned to receive theelongated member 650 therein. The frictional mounting of the housing 604to the screw member 602, described above, allows the housing 604 to betemporarily positioned until a subsequent tightening step is performed,described below.

Positioning of the housing portions 604 may be performed by the use ofan elongated surgical instrument capable of contacting and moving thehousing portion to the desired orientation. One such instrument forpositioning the housings 604 is a grasper apparatus 700, illustrated inFIG. 30. The grasper apparatus 700 includes a proximal handle portion702, an elongated body portion 704, and distal nose portion 706. Thedistal nose portion 706 includes a pair of grasping jaws 708 a and 708b, which are pivotable about pin 710 by actuation of the proximal handleportion 702. The grasping jaws 708 a and 708 b are illustrated in theclosed position in FIG. 30. Pivoting the movable handle 714 towardsstationary handle 712 causes longitudinal movement of actuator 716,which in turn pivots the jaw 708 b towards an open position (illustratedin dashed line). The biasing members 718 and 720 are provided to returnthe handles 712 and 714 to the open position and bias the jaws 708 a and708 b to the closed position.

In one application, the elongated member 650 is inserted into the accessdevice 20. In one application, the elongated member 650 is manufacturedfrom a biocompatible material and is sufficiently strong to maintain theposition of the vertebrae, or other body structures, coupled by theelongate member 650 with little or no relative motion therebetween. Inone embodiment, the elongated members 650 are manufactured from Titanium6/4 or titanium alloy. The elongated member 650 also may be manufacturedfrom stainless steel or any other suitable material. The transverseshape, width (e.g., radii), and lengths of the elongated members 650 areselected by the physician to provide the best fit for the positioning ofthe screw heads. Such selection may be performed by placing theelongated member 650 on the skin of the patient overlying the locationof the fasteners and viewed fluoroscopically. For example, a 70 mmpreformed rod having a 3.5″ bend radius may be selected for the spinalfixation.

In one application, the elongated member 650 is fixed to each of thefasteners 600, and more particularly, to the housings 604 of eachfastener 600. The grasper apparatus 700, described above, is alsoparticularly useful for inserting the elongated member 650 into theaccess device 20 and positioning it with respect to each housing 604. Asillustrated in FIG. 30, the jaws 708 a and 708 b of the grasperapparatus 700 each has shaped (e.g., curved) contact portions 722 a and722 b for contacting and holding the outer surface of the elongatedmember 650.

As illustrated in FIG. 31, the grasper apparatus 700 may be used toinsert the elongated member 650 into the operative space 90 defined atleast partially by the skirt portion 24 of the access device 20. In someembodiments, the cut-out portions 56 and 58 provided in the skirtportion 24 assist in the process of installing the elongated member 650with respect to the housings 604. The cut-out portions 56 and 58 allowan end portion 652 of the elongated member 650 to extend beyond theoperative space without raising or repositioning the skirt portion 24.The elongated member 650 is positioned within the recesses in eachhousing 604 defined by grooves 632 disposed between upright members 630and 631. The elongated member 650 is positioned in an orientationsubstantially transverse to the longitudinal axis of each housing 604.

Further positioning of the elongated member 650 may be performed byguide apparatus 800, illustrated in FIG. 32. Guide apparatus 800 isuseful in cooperation with an endoscopic screwdriver, such as endoscopicscrewdriver 660 (illustrated in FIG. 28), in order to position theelongated member 650, and to introduce and tighten the cap screw 610,described above and illustrated in FIG. 27. Tightening of the cap screw610 with respect to the housing 604 fixes the orientation of the housing604 with respect to the screw portion 602 and fixes the position of theelongated member 650 with respect to the housings 604.

In the illustrated embodiment, the guide apparatus 800 has a proximalhandle portion 802, an elongated body portion 804, and a distal toolportion 806. The elongated body portion 804 defines a central bore 808(illustrated in dashed line) along its longitudinal axis 810. Thecentral bore 808 is sized and configured to receive the endoscopicscrewdriver 660 and cap screw 610 therethrough. In the exemplaryembodiment, the diameter of the central bore 808 of the elongated bodyportion 804 is about 0.384-0.388 inches (9.75-9.86 mm) in diameter, andthe external diameter of the endoscopic screwdriver 660 (FIG. 28) isabout 0.25 inches (6.35 mm). The proximal handle portion 802 extendstransverse to the longitudinal axis 810, which allows the physician toadjust the guide apparatus 800 without interfering with the operation ofthe screwdriver 660.

The distal portion 806 of the apparatus includes several shaped cut outportions 814 which assist in positioning the elongated member 650. Asillustrated in FIG. 33, the cut out portions 814 are sized andconfigured to engage the surface of elongated member 650 and move theelongated member 650 from an initial location (illustrated in dashedline) to a desired location. In the illustrated embodiment, the cut outportions 814 are semicircular, to match the round elongated member 650.However, other shaped cut out portions may be provided to match othershaped elongated members.

As illustrated in FIG. 34, the guide apparatus 800 is used incooperation with the endoscopic screwdriver 660 to attach the cap screw610. The distal end of the body portion 804 includes a pair of elongatedopenings 816. The openings 816 provide a window to enable the physicianto endoscopically view the cap screw 610 retained at the distal tip 666of the endoscopic screw driver 660. Fewer or more than two openings canbe provided and the openings 816 need not be elongated.

The guide apparatus 800 and the endoscopic screwdriver 660 cooperate asfollows in one application. The guide apparatus 800 is configured to bepositioned in a surrounding configuration with the screwdriver 600. Inthe illustrated embodiment, the body portion 804 is configured forcoaxial placement about the screwdriver 660 in order to distribute thecontact force of the guide apparatus 800 on the elongated member 650.The distal portion 806 of the guide apparatus 800 may bear down on theelongated member 650 to seat the elongated member 650 in the notches 632in the housing 604. The “distributed” force of the guide apparatus 800may contact the elongated member 650 on at least one or more locations.In addition, the diameter of central bore 808 is selected to bemarginally larger than the exterior diameter of cap screw 610, such thatthe cap screw 610 may freely slide down the central bore 808, whilemaintaining the orientation shown in FIG. 34. This configuration allowsthe physician to have effective control of the placement of the capscrew 610 into the housing 604. The cap screw 610 is releasably attachedto the endoscopic screwdriver 660 by means of spring member 672 engagedto the interior wall of hexagonal recess 611 as it is inserted withinthe bore 808 of the body portion 804 of guide apparatus 800. The capscrew 610 is attached to the housing 604 by engaging the threads 615 ofthe cap screw 610 with the threads 634 of the housing.

As illustrated in FIG. 35, tightening of the cap screw 610 fixes theassembly of the housing 604 with respect to the elongated member 650. Inparticular, the distal surface of the cap screw 610 provides a distalforce against the elongated member 650, which in turn drives the spacermember 606 against the joint portion 614 of the screw portion 602, whichis fixed with respect to the housing 604.

If locations of the vertebrae are considered acceptable by thephysician, then the fixation procedure is substantially complete oncethe cap screws 610 have been attached to the respective housings 604,and tightened to provide a fixed structure as between the elongatedmember 650 and the various fasteners 600. However, if compression ordistraction of the vertebrae with respect to one another is requiredadditional apparatus would be used to shift the vertebrae prior to finaltightening all of the cap screws 610.

In the illustrated embodiment, this step is performed with a surgicalinstrument, such as a compressor-distractor instrument 900, illustratedin FIG. 36, which is useful to relatively position bone structures inthe cephcaudal direction and to fix their position with respect to oneanother. Thus, the compressor-distractor instrument 900 has thecapability to engage two fasteners 600 and to space them apart whilesimultaneously tightening one of the fasteners to fix the spacingbetween the two vertebrae, or other bone structures. Moreover, thecompressor-distractor instrument 900 may also be used to move twofasteners 600, and the vertebrae attached thereto into closerapproximation and fix the spacing therebetween.

The distal tool portion 902 of one embodiment of thecompressor-distractor instrument 900 is illustrated in FIG. 36. Thedistal tool portion 902 includes a driver portion 904 and a spacingmember 906. The driver portion 904 has a distal end portion 908 with aplurality of wrenching flats configured to engage the recess 611 in theproximal face of the cap screw 610, and to apply torque to the capscrew. The driver portion 904 is rotatable about the longitudinal axis(indicated by arrow M) to rotate the cap screw 610 relative to thefastener 600. Accordingly, the driver portion 904 can be rotated toloosen the cap screw 610 on the fastener 600 and permit movement of theelongated member 650 connected with the vertebra relative to thefastener 600 connected with the vertebra. The cap screw 610 can also berotated in order to tighten the cap screw 610 and clamp the elongatedmember 650 to the fastener 600.

The distal tool portion 902 may also include a spacing member, such asspacing member 906, which engages an adjacent fastener 600 b whiledriver member 904 is engaged with the housing 604 a to move the fastener600 b with respect to the fastener 600 a. In the exemplary embodiment,spacing member 906 comprises a jaw portion that is pivotably mounted tomove between a first position adjacent the driver portion and a secondposition spaced from the driver portion, as shown in FIG. 36. The distaltip 910 of the spacing member 906 is movable relative to the driverportion 904 in a direction extending transverse to the longitudinalaxis. (Further details and features related to compressor-distractorapparatuses are described in U.S. application Ser. No. 10/178,875, filedJun. 24, 2002, entitled “SURGICAL INSTRUMENT FOR MOVING VERTEBRAE,”published as U.S. Patent Application Publication No. 2003/0236529A1 onDec. 25, 2003, which is incorporated by reference in its entiretyherein. Also, further details and features related to other apparatusesfor manipulating implants and bone segments (e.g., vertebrae) to whichimplants are coupled are described in U.S. Pat. No. 6,648,888, issuedNov. 18, 2003, entitled “SURGICAL INSTRUMENT FOR MOVING VERTEBRAE.”)

As illustrated in FIG. 36, the spacer member 906 can be opened withrespect to the driver portion 904 to space the vertebrae farther apart(as indicated by arrow N). The distal portion 910 of the spacer member906 engages the housing 604 b of fastener 600 b and moves fastener 600 bfurther apart from fastener 600 a to distract the vertebrae. Where thevertebrae are to be moved closer together, e.g. compressed, the spacermember 906 is closed with respect to the driver portion 904 (arrow P),as illustrated in FIG. 37. The distal portion 910 of the spacer member906 engages the housing 604 b of the fastener 600 b and moves thefastener 600 b towards the fastener 600 a. When the spacing of thevertebrae is acceptable to the physician, the cap screw 610 a istightened by the driver member 904, thereby fixing the relationship ofthe housing 604 a with respect to the elongated member 650, and therebyfixing the position of the vertebrae, or other bone structures, withrespect to one another. In one application, once the elongated member650 is fixed with respect to the fasteners 600, the fixation portion ofthe procedure is substantially complete.

2. Fusion Systems and Devices

Although fixation may provide sufficient stabilization, in some cases itis also desirable to provide additional stabilization. For example,where one or more discs has degraded to the point that it needs to bereplaced, it may be desirable to position an implant, e.g., a fusiondevice, a prosthetic disc, a disc nucleus, etc., in the intervertebralspace formerly occupied by the disc.

In one application, a fusion device is inserted between adjacentvertebrae V. Portions of the fusion procedure can be performed before,during, or after portions of the fixation procedure. FIGS. 38-42illustrate one embodiment of a fusion device, referred to herein as aspinal implant 2010, that is inserted between adjacent vertebrae. Thespinal implant 2010 preferably is placed between adjacent vertebrae toprovide sufficient support to allow fusion of the adjacent vertebrae, asshown in FIGS. 48-49. The spinal implants 2010 are preferably made froman allograft material, though other materials could also be used,including autograft, xenograft, or some non-biologic biocompatiblematerial, such as titanium or stainless steel. Also, where non-biologicmaterials are used, the implant 2010 may be configured as a cage orother suitable configuration.

The spinal implant 2010 (FIGS. 38-42) has a first end 2020 for insertionbetween adjacent vertebrae V. The first end 2020 has a tapered surface2022 to facilitate insertion of the implant between adjacent vertebraeV. The surface 2022 defines an angle X of approximately 45° as shown inFIG. 41.

The spinal implant 2010 (FIGS. 38-39) has a second end 2030 that isengageable with a tool 2032 (FIG. 51) for inserting the implant betweenthe adjacent vertebrae V. The tool 2032 has a pair of projections 2034,one of which is shown in FIG. 51, that extend into recesses 2036 and2038 in the end 2030 of the implant 2010. The recesses 2036 and 2038(FIGS. 38-39) extend from the second end 2030 toward the first end 2020.The recess 2036 (FIG. 41) is defined by an upper surface 2040 and alower surface 2042 extending generally parallel to the upper surface2040. The recess 2038 (FIG. 39) has a lower surface 2046 and an uppersurface 2048. The upper surface 2048 extends generally parallel to thelower surface 2046.

The recesses 2036 and 2038 define a gripping portion 2052. Theprojections 2034 on the tool 2032 extend into the recesses 2036 and 2038and grip the gripping portion 2052. The projections 2034 engage theupper and lower surfaces 2040 and 2042 of the recess 2036 and the upperand lower surfaces 2046 and 2048 of the recess 2038. Accordingly, thetool 2032 can grip the implant 2010 for inserting the implant betweenthe adjacent vertebrae V.

As viewed in FIGS. 38-41, the implant 2010 has an upper surface 2060 forengaging the upper vertebra V. The implant 2010 has a lower surface2062, as viewed in FIGS. 38-41, for engaging the lower vertebra V. Theupper and lower surfaces 2060 and 2062 extend from the first end 2020 tothe second end 2030 of the implant 2010 and parallel to the upper andlower surfaces 2040, 2042, 2046, and 2048 of the recesses 2036 and 2038.The upper surface 2060 has teeth 2064 for engaging the upper vertebra V.The lower surface 2062 has teeth 2066 for engaging the lower vertebra V.Although FIGS. 38-39 show four teeth 2064 and four teeth 2066, it iscontemplated that any number of teeth could be used.

A first side surface 2070 and a second side surface 2072 extend betweenthe upper and lower surfaces 2060 and 2062. The first side surface 2070extends along a first arc from the first end 2022 of the implant 2010 tothe second end 2030. The second side surface 2072 extends along a secondarc from the first end 2022 to the second end 2030. The first and secondside surfaces 2070 and 2072 are concentric and define portions ofconcentric circles. The teeth 2064 and 2066 extend parallel to eachother and extend between the side surfaces 2070 and 2072 and alongsecant lines of the concentric circles defined by the side surfaces.

The implant 2010 preferably is formed by harvesting allograft materialfrom a femur, as known in the art. The femur is axially cut to formcylindrical pieces of allograft material. The cylindrical pieces arethen cut in half to form semi-cylindrical pieces of allograft material.The semi-cylindrical pieces of allograft material are machined into thespinal implants 2010.

A pair of spinal implants 2010 may be placed bilaterally between theadjacent vertebrae V. The access device 20 is positioned in thepatient's body adjacent the vertebrae V. The skirt portion 24 of theaccess device 20 preferably is in a radially expanded condition toprovide a working space adjacent the vertebrae V as described above.Disc material between the vertebrae V can be removed using instrumentssuch as kerrisons, rongeurs, or curettes. A microdebrider may also beutilized to remove the disc material. An osteotome, curettes, andscrapers can be used to prepare end plates of the vertebrae V forfusion. Preferably, an annulus of the disc is left between the vertebraeV.

Distracters can be used to sequentially distract the disc space untilthe desired distance between the vertebrae V is achieved. The fusiondevice or implant 2010 is placed between the vertebrae V using the tool2032. The first end 2020 of the implant 2010 is inserted first betweenthe vertebrae V. The implant 2010 is pushed between the vertebrae Vuntil the end 2030 of the implant is between the vertebrae. A secondspinal implant 2010 is inserted on the ipsilateral side using the sameprocedure.

A shield apparatus 3100 with an elongated portion 3102 may be used tofacilitate insertion of the implants 2010 between the vertebrae V. Adistal portion 3110 of the apparatus 3100 may be placed in anannulotomy. The implant 2010 is inserted with the side surface 2170facing the elongated portion 3102 so that the apparatus 3100 can act asa “shoe horn” to facilitate or guide insertion of the implants 2010between the vertebrae.

The implants 2010 may be inserted between the vertebrae V with the firstends 2020 located adjacent each other and the second ends 2030 spacedapart from each other, as shown in FIG. 48. The implants 2010 may alsobe inserted between the vertebrae V with the first ends 2020 of theimplants 2010 spaced apart approximately the same distance that thesecond ends 2030 are spaced apart. It is contemplated that the implants2010 may be inserted in any desired position between the vertebrae V. Itis also contemplated that in some embodiments only one implant 2010 maybe inserted between the vertebrae V. Furthermore, it is contemplatedthat the implants 2010 may be inserted between vertebrae using an openprocedure.

Another embodiment of a fusion device or spinal implant 2110 isillustrated in FIGS. 43-47. The spinal implant 2110 is substantiallysimilar to the embodiment disclosed in FIGS. 38-42. The implant 2110 isplaced between the adjacent vertebrae V to provide sufficient support toallow fusion of the adjacent vertebrae, as shown in FIG. 50. The spinalimplant 2110 is preferably made from an allograft material, though thematerials described above in connection with the spinal implant 2010 mayalso be used. Also, as with the implant 2010, the implant 2110 may beformed as a cage or other suitable configuration.

The spinal implant 2110 (FIGS. 43-47) has a first end 2120 for insertionbetween the adjacent vertebrae V. The first end 2120 has a taperedsurface 2122 to facilitate insertion of the implant between the adjacentvertebrae V. The surface 2122 defines an angle Y of approximately 45° asshown in FIG. 65.

The spinal implant 2110 (FIGS. 43-44) has a second end 2130 that isengageable with the projections 2034 on the tool 2032 for inserting theimplant between the adjacent vertebrae V. The projections 2034 extendinto recesses 2136 and 2138 in the end 2130 of the implant 2110. Therecesses 2136 and 2138 extend from the second end 2130 toward the firstend 2120. The recess 2136 (FIGS. 43 and 46) is defined by an uppersurface 2140 and a lower surface 2142 extending generally parallel tothe upper surface 2140. The recess 2138 (FIG. 44) has a lower surface2146 and an upper surface 2148 extending generally parallel to the lowersurface 2146.

The recesses 2136 and 2138 define a gripping portion 2152. Theprojections 2034 on the tool 2032 extend into the recesses 2136 and 2138and grip the gripping portion 2152. The projections 2034 engage theupper and lower surfaces 2140 and 2142 of the recess 2136 and the upperand lower surfaces 2146 and 2148 of the recess 2138. Accordingly, thetool 2032 can grip the implant 2110 for inserting the implant betweenthe adjacent vertebrae V.

As viewed in FIGS. 43-46, the implant 2110 has an upper surface 2160 forengaging the upper vertebra V. The implant 2110 has a lower surface2162, as viewed in FIGS. 43-46, for engaging the lower vertebra V. Theupper and lower surfaces 2160 and 2162 extend from the first end 2120 tothe second end 2130 of the implant 2110 and parallel to the upper andlower surfaces 2140, 2142, 2146, and 2148 of the recesses 2136 and 2138.The upper surface 2160 has teeth 2164 for engaging the upper vertebra V.The lower surface 2162 has teeth 2166 for engaging the lower vertebra V.Although FIG. 44 shows four teeth 2164 and four teeth 2166, it iscontemplated that any number of teeth could be used.

A first side surface 2170 and a second side surface 2172 extend betweenthe upper and lower surfaces 2160 and 2162. The first side surface 2170extends along a first arc from the first end 2122 of the implant 2110 tothe second end 2130. The second side surface 2172 extends along a secondarc from the first end 2120 to the second end 2130. The first and secondside surfaces 2170 and 2172 are concentric and define portions ofconcentric circles. The teeth 2164 and 2166 extend parallel to eachother and between the side surfaces 2170 and 2172 along secant lines ofthe concentric circles defined by the side surfaces.

The implant 2110 preferably is formed by harvesting allograft materialfrom a femur, as is known in the art. The femur is axially cut to formcylindrical pieces of allograft material. The cylindrical pieces arethen cut in half to form semi-cylindrical pieces of allograft material.The semi-cylindrical pieces of allograft material are machined into thespinal implants 2110.

A spinal implant 2110 is placed unilaterally between the adjacentvertebrae V. The access device 20 is positioned in the patient's bodyadjacent the vertebrae V. The skirt portion 24 of the access device 20preferably is in a radially expanded condition to provide a workingspace adjacent the vertebrae V as described above. Disc material betweenthe vertebrae V can be removed using instruments such as kerrisons,rongeurs, or curettes. A microdebrider may also be utilized to removethe disc material. An osteotome, curettes, and scrapers can be used toprepare end plates of the vertebrae V for fusion. Preferably, an annulusof the disc is left between the vertebrae V.

Distracters are used to sequentially distract the disc space until thedesired distance between the vertebrae V is achieved. The implant 2110is placed between the vertebrae V using the tool 2032. It iscontemplated that the apparatus 3100 could be used also. The first end2120 of the implant 2110 is inserted first between the vertebrae V. Theimplant 2110 is pushed between the vertebrae V until the end 2130 of theimplant is between the vertebrae. It is contemplated that the implant2110 may be inserted in any desired position between the vertebrae V. Itis also contemplated that in some embodiments more than one implant 2110may be inserted between the vertebrae.

The apparatus or shield 3100 for use in placing the fusion devices orspinal implants between the vertebrae is illustrated in FIGS. 52-56. Theapparatus 3100 preferably includes an elongated body portion 3102, whichprotects the nerve root or dura, and a mounting portion 3104, whichallows for the surgeon to releasably mount the apparatus 3100 to theaccess device 20. Consequently, the surgeon is able to perform thesurgical procedures without requiring the surgeon or an assistant tocontinue to support the apparatus 3100 throughout the procedure, andwithout reducing the field of view.

The apparatus 3100 may be manufactured from a biocompatible materialsuch as, for example, stainless steel. In the illustrated embodiment,apparatus 3100 is manufactured from stainless steel having a thicknessof about 0.02 inches (0.508 mm) to about 0.036 inches (0.914 mm). Theelongated body portion 3102 has dimensions that correspond to the depthin the body in which the procedure is being performed, and to the sizeof the body structure that is to be shielded by elongated body portion3102. In the exemplary embodiment, the elongated body portion 3102 has awidth 3106 of about 0.346 inches (8.79 mm) and a length of about 5.06inches (128.5 mm) (FIG. 53), although other dimensions would beappropriate for spinal surgical procedures performed at differentlocations, or for surgical procedures involving different bodystructures. The distal tip portion 3110 of the apparatus 3100 may have aslightly curved “bell mouth” configuration which allows for atraumaticcontact with a body structure, such as a nerve. It is contemplated thatthe elongated body portion may have any desired shape.

The mounting portion 3104 preferably allows the apparatus 3100 to besecured to a support structure in any number of ways. In the exemplaryembodiment, mounting portion 3104 may include a ring portion. Withreference to FIGS. 52-56, ring portion 3120 has a substantiallyring-shaped configuration with an opening 3124, which defines an angle3126 of about 90 degrees of the total circumference of the ring portion3120. As will be described in greater detail below, the angle 3126 is anominal value, because the ring portion 3104 is resilient, which permitsthe opening 3124 to change size during the mounting process.

In the illustrated embodiment, the mounting portion 3104 has asubstantially cylindrical configuration in order to be mounted withinthe interior lumen of the access device 20, as will be described below.The ring portion 3104 has an exterior dimension 3130 of about 0.79inches (20.1 mm), and an interior dimension 3132 of about 0.76 inches(19.3 mm). It is understood that the dimensions of the ring portion 3104can be different, such as, for example, where the access device 20 has adifferent interior dimension. Moreover, the cylindrical shape of thering portion 3104 can change, such as, for example, where the apparatus3100 is used with a support member having a differently shaped internallumen.

Finger grip portions 3122 preferably extend from the mounting portion1304 and allow the surgeon to apply an inwardly directed force (asindicated by arrows A) to the ring portion 3120. The resilientcharacteristics of the ring portion 3120 allow the material to deflectthereby reducing the exterior dimension 3130 and reducing the spacing3124. Releasing the finger grip portions 3122 allows the ring portion tomove towards its undeflected condition, thereby engaging the interiorwall of the access device 20.

The elongated body portion 3102 and the mounting portion 3104 may bemanufactured from a single component, such as a sheet of stainlesssteel, and the mounting portion 3104 may be subsequently formed into asubstantially cylindrical shape. In another embodiment, the mountingportion 3104 may be manufactured as a separate component and coupledwith the elongated body portion, by techniques such as, for example,welding and/or securement by fasteners, such as rivets.

The access device 20 serves as a stable mounting structure for apparatus3100. In particular, mounting portion 3104 is releasably mounted to theinterior wall of proximal wall portion 22 of access device 20. Elongatedbody portion 3102 extends distally into the operative site to protectthe desired body structure, such as the nerve, as will be describedbelow.

To install the apparatus 3100 within the interior passage of theproximal wall portion 22, the surgeon may apply an inwardly directedforce on the ring portion 3120, thereby causing the ring portion toresiliently deform, as illustrated by dashed line and arrows B in FIG.59. The surgeon subsequently inserts the apparatus 3100 into theinterior lumen of the proximal wall portion 22 (as indicated by arrow C)to the position of ring portion 3104 illustrated in solid line in FIG.58. When the surgeon releases the finger grip portions 3122, the ringportion 3120 resiliently moves towards its undeflected configuration,thereby engaging the interior lumen of the proximal wall portion 22.Advantages of some embodiments include that the mounting portion 3104 iseasily removed and/or moved with respect to the access device 20 withoutdisturbing the position of the access device 20 or any otherinstrumentation.

As illustrated in FIG. 57, the configuration of the mounting portion3104 and the elongated body portion 3102 allow the elongated bodyportion to occupy a small space along the periphery of the proximal wallportion 3122. This allows the apparatus to protect the desired bodystructure without blocking access for the insertion of other surgicalinstrumentation, and without blocking visibility by the surgeon duringthe procedure.

The mounting portion 3104 is one exemplary configuration for mountingthe apparatus 3100 to the support structure. It is contemplated that theapparatus 3100 may be mounted within the access device 20 in anysuitable manner.

When in position, the distal end portion 3110 covers the exiting nerveroot R, while exposing the disc annulus A (See FIG. 57). As discussedabove, the debridement and decortication of tissue covering thevertebrae, as well as a facetectomy and/or laminectomy if indicated, arepreferably performed prior to the insertion of apparatus 3100 into thesurgical space. Accordingly, in some embodiments, there is no need todisplace or retract tissue, and apparatus 3100 merely covers the nerveroot and does not substantially displace the nerve root or any otherbody tissue. It is understood that the term “cover” as used hereinrefers to apparatus 3100 being adjacent to the body structure, or incontact with the body structure without applying significant tension ordisplacement force to the body structure.

Additional surgical instrumentation S may be inserted into the accessdevice to perform procedures on the surrounding tissue. For example, anannulotomy may be performed using a long handled knife and kerrisons. Adiscectomy may be completed by using curettes and rongeurs. Removal ofosteophytes which may have accumulated between the vertebrae may beperformed using osteotomes and chisels.

As illustrated in FIG. 60, the elongated body portion 3102 preferably isrotated to protect the spinal cord, or dura D, during the aboveprocedures. The surgeon may change the position of the apparatus 3100 byapproximating the finger grips 3122 to release the ring portion fromengagement with the inner wall of the proximal wall portion 20, and thenre-position the apparatus 3100 without disturbing the access device 20(as shown in FIG. 58).

During certain surgical procedures, it may be useful to introducecrushed bone fragments or the fusion devices 2010 or 2110 to promotebone fusion. As illustrated in FIGS. 61-62, apparatus 3100 is useful todirect the implants into the space I between adjacent vertebrae V. Asshown in the figures, the distal portion 3110 of the elongated bodyportion 3102 is partially inserted into the space I. The distal endportion 3110, is positioned between adjacent vertebrae V, and creates apartially enclosed space for receiving the implants or other materialtherein.

Another embodiment of the apparatus or shield is illustrated in FIGS.63-64, and designated apparatus 3200. Apparatus 3200 is substantiallyidentical to apparatus 3100, described above, with the followingdifferences noted herein. In particular, distal end portion 3210includes a pair of surfaces 3240 and 3242. Surface 3240 is an extensionof elongated shield portion 3202, and surface 3242 extends at an anglewith respect to surface 3240. In the exemplary embodiment, surfaces 3240and 3242 defined an angle of about 90 degrees between them.Alternatively another angle between surfaces 3240 and 3242 may bedefined as indicated by the body structures to be protected.

Distal end portion 3210 allows the apparatus to provide simultaneousshielding of both the dura D and the nerve root R. In FIGS. 65-66,surface 3242 shields the dura D, and surface 3240 shields the nerve rootR. It is understood that surfaces 3240 and 3242 may be interchanged withrespect to which tissue they protect during the surgical procedure.

According to the exemplary embodiment, once the fusion and fixationportions of the procedure have been performed, the procedure issubstantially complete. The surgical instrumentation, such as theendoscope 500 can be withdrawn from the surgical site. The access device20 is also withdrawn from the site. The muscle and fascia typicallyclose as the access device 20 is withdrawn through the dilated tissuesin the reduced profile configuration. The fascia and skin incisions areclosed in the typical manner, with sutures, etc. The procedure describedabove may be repeated for the other lateral side of the same vertebrae,if indicated.

II. Surgical Procedures that May be Performed with the Systems DescribedHerein

As discussed above, the systems disclosed herein provide access to asurgical location at or near the spine of a patient to enable procedureson the spine. These procedures can be applied to one or more vertebrallevels, as discussed above. Additional procedures and combinations ofprocedures that may be performed using the systems described herein arediscussed below. In various forms, these procedures involve an anteriorlumbar interbody fusion, a minimally invasive lumbar interbody fusion,and other procedures particularly enabled by the access devices andsystems described above.

A. Procedures Involving Anterior Lumbar Interbody Fusion

The access devices and systems described herein are amenable to avariety of procedures that may be combined with an anterior lumbarinterbody fusion (referred to herein as an “ALIF”).

In one embodiment of a first method, three adjacent vertebrae, such asthe L4, the L5, and the S1 vertebrae of the spine, are treated by firstperforming an ALIF procedure. Such a procedure may be performed in aconvention manner. The ALIF involves exposing a portion of the spine, inparticular the vertebrae and discs located in the interbody spaces,i.e., the spaces between adjacent vertebrae. Any suitable technique forexposing the interbody spaces may be employed, e.g., an open, mini-open,or minimally invasive procedure. In one embodiment, the interbody spacesbetween the L4, L5, and S1 vertebrae are exposed to the surgeon. Onceexposed, the surgeon may prepare the interbody space, if needed, in anysuitable manner. For example, some or all of the disc may be removedfrom the interbody space and the height of the interbody space may beincreased or decreased. The interbody space between the L4 and the L5vertebrae may be exposed separately from the interbody space between theL5 and S1 vertebrae or they may be generally simultaneously exposed andprepared.

After the interbody space has been exposed and prepared, a suitablefusion procedure may be performed. For example, in one example fusionprocedure, one or more fusion devices may be placed in the interbodyspace. Any suitable fusion device may be used, e.g., a fusion cage, afemoral ring, or another suitable implant. Various embodiments ofimplants and techniques and tools for the insertion of implants aredescribed in U.S. application Ser. No. 10/280,489, filed Oct. 25, 2002,which has been published as Publication No. 2003/0073998 on Apr. 17,2003, which is hereby incorporated by reference herein in its entirety.In one variation, one or more fusion cages may be placed in an interbodyspace, e.g., between the L4 and L5 vertebrae, between the L5 and S1vertebrae, or between the L4 and L5 vertebrae and between the L5 and S1vertebrae. In another variation, one or more femoral rings may besubstituted for one or more of the fusion cages and placed between theL4 and L5 vertebrae and/or between the L5 and S1 vertebrae. In anothervariation, one or more fusion devices are combined with a bone growthsubstance, e.g., bone chips, to enhance bone growth in the interbodyspace(s).

After anterior placement of the fusion device, an access device isinserted into the patient to provide access to a spinal location, asdescribed above. A variety of anatomical approaches may be used toprovide access to a spinal location using the access device 20. Theaccess device preferably is inserted generally posteriorly. As usedherein the phrase “generally posteriorly” is used in its ordinary senseand is a broad term that refers to a variety of surgical approaches tothe spine that may be provided from the posterior side, i.e., the back,of the patient, and includes, but is not limited to, posterior,postero-lateral, and transforaminal approaches. Any of the accessdevices described or incorporated herein, such as the access device 20,could be used.

The distal end of the access device may be placed at the desiredsurgical location, e.g., adjacent the spine of the patient with acentral region of the access device over a first vertebrae. In oneprocedure, the distal end of the access device is inserted until itcontacts at least a portion of at least one of the vertebrae beingtreated or at least a portion of the spine. In another procedure, thedistal end of the access device is inserted until it contacts a portionof the spine and then is withdrawn a small amount to provide a selectedgap between the spine and the access device. In other procedures, theaccess device may be inserted a selected amount, but not far enough tocontact the vertebrae being treated, the portion of the vertebrae beingtreated, or the spine.

The access device may be configured, as described above, to provideincreased access to the surgical location. The access device can have afirst configuration for insertion to the surgical location over thefirst vertebra and a second configuration wherein increased access isprovided to the adjacent vertebrae. The first configuration may providea first cross-sectional area at a distal portion thereof. The secondconfiguration may provide a second cross-sectional area at the distalportion thereof. The second cross-sectional area preferably is enlargedcompared to the first cross-sectional area. In some embodiments, theaccess device may be expanded from the first configuration to the secondconfiguration to provide access to the adjacent vertebrae above andbelow the first vertebra.

When it is desired to treat the L4, L5, and S1 vertebrae, the accessdevice may be inserted over the L5 vertebrae and then expanded toprovide increased access to the L4 and S1 vertebrae. In one embodiment,the access device can be expanded to an oblong shaped configurationwherein the access device provides a first dimension of about 63 mm, anda second dimension perpendicular to the first dimension of about 24 mm.In another embodiment, the access device can be expanded to provide afirst dimension of about 63 mm, and a second dimension perpendicular tothe first dimension of about 27 mm. These dimensions provide a surgicalspace that is large enough to provide access to at least three adjacentvertebrae without exposing excessive amounts of adjacent tissue that isnot required to be exposed for the procedures being performed. Otherdimensions and configurations are possible that would provide the neededaccess for procedures involving three adjacent vertebrae.

When the access device is in the second configuration, fixation of thethree vertebrae may be performed. As discussed above, fixation is aprocedure that involves providing a generally rigid connection betweenat least two vertebrae. Any of the fixation procedures discussed abovecould be used in this method, as could other fixation procedures. Onefixation procedure that could be used is discussed above in connectionwith FIG. 36 wherein the fasteners 600 a, 600 b, and 600 c are advancedthrough the access device 20 to three adjacent vertebrae and areattached to the vertebrae. The three fasteners 600 a, 600 b, and 600 care interconnected by the elongated member 650. The three fasteners 600a, 600 b, and 600 c and the elongate member 650 comprise a firstfixation assembly. A second fixation assembly may be applied to thepatient on the opposite side of the spine, i.e., about the same locationon the opposite side of the medial line of the spine. Other fixationprocedures could be applied, e.g., including two fasteners that coupledwith the L4 and the S1 vertebrae and an elongate member interconnectingthese vertebrae.

One variation of the first method provides one level of fixation on theanterior side of the patient, e.g., when the fusion device is placed inthe interbody space. For example, fixation of the L5 and S1 vertebraecould be provided on the anterior side of the spine, in addition to theother procedures set forth above (e.g., a two level postero-lateralfixation). Also, fixation of the L4 and L5 vertebrae could be providedon the anterior side of the spine, in addition to the other proceduresset forth above (e.g., a two level postero-lateral fixation).

In a second method, substantially the same steps as set forth above inconnection with the first method would be performed. In addition, afterthe access device is inserted, a decompression procedure is performedthrough the access device. A decompression procedure is one whereunwanted bone is removed from one or more vertebrae. Unwanted bone caninclude stenotic bone growth, which can cause impingement on theexisting nerve roots or spinal cord. Decompression procedures that maybe performed include laminectomy, which is the removal of a portion of alamina(e), and facetectomy, which is the removal of a portion of one ormore facets. In one variation of this method, decompression includesboth a facetectomy and a laminectomy. Any suitable tool may be used toperform decompression. One tool that is particularly useful is akerrison.

In a third method, substantially the same steps as set forth above inconnection with the first method would be performed. That is, an ALIFprocedure is performed in combination with a fixation procedure. Inaddition, a fusion procedure may be performed through the access devicewhich may have been placed generally posteriorly, e.g.,postero-laterally, tranforaminally or posteriorly, whereby bone growthis promoted between the vertebrae and the fixation assembly, includingat least one of the fasteners 600 a, 600 b, 600 c and/or the elongateelement 650. This procedure is also referred to herein as an “externalfusion” procedure.

One example of an external fusion procedure that may be performedinvolves placement of a substance through the access device intended toencourage bone growth in and around the fixation assembly. Thus, fusionmay be enhanced by placing a bone growth substance adjacent any of thefasteners 600 a, 600 b, 600 c and/or the elongate member 650. The bonegrowth substance may take any suitable form, e.g., small bone chipstaken from the patient (e.g., autograft), from another donor source(e.g., allograft or xenograft), and orthobiologics.

After the bone growth substance is applied to the fixation assembly, theaccess device is removed. Absent the retracting force provided by theaccess device, the patient's tissue generally collapses onto the bonegrowth substance. The tissue will thereby maintain the position of thebone growth substance adjacent to the fixation assembly. The presence ofthe bone growth substance can cause bone to bridge across from thevertebra(e) to one or more components of the fixation assembly.

In a fourth method, substantially the same steps as set forth above inconnection with the second method would be performed. That is, an ALIFprocedure is performed anteriorly, and a decompression procedure and afixation procedure are performed through the access device which may beplaced generally posteriorly, e.g., postero-laterally, tranforaminally,or posteriorly. In addition, bone growth substance is placed in andaround a fixation assembly through the access device, as discussed abovein connection with the third method. The bone growth substanceencourages bone to bridge across from the vertebrae to the fixationassembly.

In a fifth method, an ALIF procedure is performed, as discussed above inconnection with the second method. After one or more fusion devices isplaced in the interbody space, access is provided by way of the accessdevice, as discussed above, from any suitable anatomical approach, e.g.,a generally posterior approach. Preferably, a postero-lateral approachis provided. After access has been provided, a bone growth substance,such as those discussed above in connection with the third method, isdelivered through the access device. The bone growth substance is placedadjacent an interbody space, e.g., the space between the L4 and the L5vertebrae and/or between the L5 and the S1 vertebrae. The bone growthsubstance encourages fusion of the adjacent vertebrae, e.g., L4 to L5and/or L5 to S1, by stimulating or enhancing the growth of bone betweenadjacent vertebrae, as discussed above.

In a sixth method, substantially the same steps described in connectionwith the first method are performed, except that the fixation procedureis optional. In one variation of the sixth method, the fixationprocedure is not performed. However, after the access device isinserted, a bone growth substance is placed in and around one or moreinterbody spaces through the access device. Where the sixth methodinvolves a two level procedure, the bone growth substance can be placedadjacent the interbody space between the L4 and the L5 vertebra and/orbetween the L5 and the S1 vertebra. Thus, bone growth may occur in theinterbody space and adjacent the interbody space between the vertebrae.

The foregoing discussion illustrates that an ALIF procedure can becombined with a variety of procedures that can be performed through anaccess device disclosed herein. In addition, though not expressly setforth herein, any combination of the procedures discussed above, and anyother suitable known procedure, may also be combined and performedthrough the access devices described herein, as should be understood byone skilled in the art.

B. Spine Procedures Providing Minimally Invasive Lumbar Interbody Fusion

Another category of procedures that may be performed with the accessdevices and systems described above involves a minimally invasive lumbarinterbody fusion (referred to herein as a “MILIF”). MILIF procedures areparticularly advantageous because they permit the surgeon to perform awide variety of therapeutic procedures without requiring fusion by wayof an anterior approach, as is required in an ALIF. This provides afirst advantage of allowing the surgeon to perform all procedures fromthe same side of the patient and also possibly from the same approach.Also, the access devices and systems disclosed herein provide thefurther advantage of enabling two level procedures, and many otherrelated procedures, to be performed by way of a single percutaneousaccess. These and other advantages are explained more fully below.

In a first MILIF method, a two level postero-lateral fixation of thespine involving three adjacent vertebrae, such as the L4, L5, and S1vertebrae, is provided. Analogous one level procedures and two levelprocedures involving any other three vertebrae also may be provided. Inaddition, the access devices and systems described herein could be usedor modified to accommodate other multi-level procedures, such as a threelevel procedure. The surgeon inserts an access device such as describedherein to a surgical location near the spine. As discussed above, theaccess devices are capable of a wide variety of anatomical approaches.In this procedure, a postero-lateral approach is preferred. Once theaccess device is inserted to a location adjacent the spine, as discussedabove, it may be configured, e.g., expanded, as discussed above, to aconfiguration wherein sufficient access is provided to the surgicallocation.

Any suitable fusion process may then be performed. For example, animplant may be advanced through the access device into the interbodyspace in order to maintain disc height and allow bone growth therein,e.g., as in a fusion procedure. In order to ease insertion of theimplant, it may be beneficial to prepare the interbody space. Interbodyspace preparation may involve removal of tissue or adjusting the heightof the interbody space through the access device, such as in adistraction procedure. Once the interbody space is prepared, a suitableimplant may be advanced through the access device into the interbodyspace, taking care to protect surrounding tissues. Various embodimentsof implants and techniques and tools for their insertion are describedin U.S. application Ser. No. 10/280,489, incorporated by referenceherein. In general, the implant preferably is an allograft strut that isconfigured to maintain disc height and allow bone growth in theinterbody space.

In addition to providing a suitable fusion, the first method providesfixation of the vertebrae. The fixation procedure may take any suitableform, e.g., any of the fixation procedures similar to those disclosedabove. In particular, when the access device is in the expanded orenlarged configuration, fixation of the three adjacent vertebrae may beperformed. One fixation procedure that could be used is discussed abovein connection with FIG. 36 wherein the fasteners 600 a, 600 b, and 600 care advanced through the access device 20 to three adjacent vertebraeand are attached to the vertebrae. The three fasteners 600 a, 600 b, and600 c are interconnected by way of the elongated member 650. Asdiscussed above, a second fixation assembly may be applied to thepatient on the opposite side of the spine, e.g., about the same locationon the opposite side of the medial line of the spine.

In a second MILIF method, substantially the same procedures set forthabove in connection with the first MILIF method are performed. Inaddition, a suitable decompression procedure may be performed, asneeded. As discussed above, decompression involves removal of unwantedbone by way of a suitable decompression technique that may be performedthrough the access device. In one embodiment, decompression is performedthrough the access device after the access device has been expanded. Asdiscussed above, suitable decompression techniques include alaminectomy, a facetectomy, or any other similar procedure.Decompression for the L4, the L5, and/or the S1 vertebrae may be neededand can be performed through the access devices described herein withoutrequiring the access device to be moved from one position to another.

In a third MILIF method, substantially the same procedures set forthabove in connection with the first MILIF method are performed. Inaddition, a further fusion procedure, e.g., a fusion procedure externalto the interbody space, is provided. The external fusion procedure isperformed adjacent to the interbody space wherein bone growth may bepromoted in the proximity of the fixation assembly, e.g., above thepostero-lateral boney elements of the spine, such as the facet jointsand the transverse processes. In one embodiment, when the fixationassembly comprising the fasteners 600 a, 600 b, 600 c and/or theelongate element 650 has been applied to three adjacent vertebrae, asubstance is applied through the access device to one or more componentsof the fixation assembly to maintain or enhance the formation and/orgrowth of bone in the proximity of the fixation assembly. For example, abone growth substance may be placed adjacent any of the fasteners 600 a,600 b, 600 c and/or the elongate member 650. Bone growth substance maytake any suitable form, e.g., small bone chips taken from the patient(e.g., autograft), from another donor source (e.g., allograft orxenograft), and orthobiologics.

After the bone growth substance is applied to the fixation assembly, theaccess device is removed. Absent the retracting force provided by theaccess device, the patient's tissue generally collapses onto the bonegrowth substance. The tissue will thereby maintain the position of thebone growth substance adjacent to the fixation assembly. The presence ofthe bone growth substance advantageously causes bone to grow between thevertebrae and the fixation assembly to form a bridge therebetween.

A fourth MILIF method involves substantially the same proceduresperformed in connection with the third MILIF method. In particular, oneor more implants are positioned in the interbody spaces through anaccess device, a fixation procedure is performed through the accessdevice, and a further fusion procedure is performed wherein bone growthsubstance is positioned adjacent the interbody space through the accessdevice. In addition, a decompression procedure is performed through theaccess device that may include a facetectomy and/or a laminectomy.

A fifth MILIF method involves substantially the same proceduresperformed in connection with the first MILIF method, except that thefixation is optional. In one embodiment, the fixation is not performed.In addition, a further fusion procedure is performed through the accessdevice wherein bone growth substance is positioned adjacent theinterbody space, as discussed above.

A sixth MILIF method is substantially the same as the fifth MILIFmethod, except that a further fusion procedure is performed through theaccess device. In particular, an implant is positioned in the interbodyspace through an access device, a decompression procedure is performedthrough the access device, and a further fusion procedure is performedwhereby bone growth substance is placed adjacent the interbody spacethrough the access device. As discussed above, the decompressionprocedure may include a facetectomy, a laminectomy, and any othersuitable procedure. As with any of the methods described herein, theprocedures that make up the sixth MILIF method may be performed in anysuitable order. Preferably the decompression procedure is performedbefore the external fusion procedure.

The foregoing discussion illustrates that a MILIF procedure can includea variety of procedures that can be performed through an access devicedescribed herein. In addition, though not expressly set forth herein,any combination of the procedures discussed above, and any othersuitable known procedures, may also be combined, as should be understoodby one skilled in the art.

C. Other Multi-level Procedures

While the foregoing procedures have involved interbody fusion, theaccess devices and systems described herein can be employed in a varietyof single level and multi-level procedures (e.g., more than two levels)that do not involve an interbody fusion. For example, a discectomy canbe performed through the access devices described herein withoutimplanting an interbody fusion device thereafter, e.g., to remove aherneation. In another embodiment, a discectomy can be performed in morethan one interbody space without inserting an interbody fusion deviceinto each interbody space, e.g., to remove multiple herneations. Inanother embodiment, a single or multi-level decompression procedure canbe performed to remove unwanted bone growth.

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications,alterations, and combinations can be made by those skilled in the artwithout departing from the scope and spirit of the invention. Someadditional features and embodiments are described below.

III. Additional Features and Embodiments of Systems and Methods forPerforming Surgical Procedures

FIGS. 67-75 illustrate various embodiments of another access devicedesignated by reference number 5000. The term “access device” is used inits ordinary sense to mean a device that can provide access and is abroad term and it includes structures having an elongated dimension anddefining a passage, e.g., a cannula or a conduit. With reference toFIGS. 67 and 68, the access device 5000 is configured to be insertedthrough the skin of the patient to provide access during a surgicalprocedure to a surgical location within a patient, e.g., a spinallocation. The term “surgical location” is used in its ordinary sense(i.e. a location where a surgical procedure is performed) and is a broadterm and it includes locations subject to or affected by a surgery. Theterm “spinal location” is used in its ordinary sense (i.e. a location ator near a spine) and is a broad term and it includes locations adjacentto or associated with a spine that may be sites for surgical spinalprocedures. The access device 5000 also can retract tissue to providegreater access to the surgical location.

The access device 5000 has an elongate body 5002 that has a proximal end5004 and a distal end 5006. With reference to FIGS. 67 and 68, theelongate body 5002 has a length 5008 between the proximal end 5004 andthe distal end 5006. The length 5008 is selected such that when theaccess device 5000 is applied to a patient during a surgical procedure,the distal end 5006 can be positioned inside the patient adjacent thespinal location. When so applied, the proximal end 5004 is preferablyoutside the patient at a suitable height, as discussed more fully below.

In one embodiment, the elongate body 5002 comprises a proximal portion5010 and a distal portion 5012. The proximal portion 5010 has an oblongor generally oval shaped cross section in one embodiment. The term“oblong” is used in its ordinary sense (i.e., having an elongated form)and is a broad term and it includes a structure having a dimension,especially one of two perpendicular dimensions, such as, for example,width or length, that is greater than another and includes shapes suchas rectangles, ovals, ellipses, triangles, diamonds, trapezoids,parabolas, and other elongated shapes having straight or curved sides.The term “oval” is used in its ordinary sense (i.e., egg like orelliptical) and is a broad term and includes oblong shapes having curvedportions.

The distal portion 5012 is expandable in one embodiment. At least onepassage 5014 extends through the elongate body 5002 between the proximalend 5004 and the distal end 5006, e.g., through the proximal and distalportions 5010, 5012. The passage 5014 is defined by a smooth metal innersurface 5016 that extends substantially entirely around the perimeter ofthe passage 5014 between the proximal and distal ends 5004, 5006 in oneembodiment. The inner surfaces 5016 can take other forms, e.g.,employing other materials, different but generally constant smoothness,and/or varying degrees of smoothness.

In one embodiment, the elongate body 5002 is expandable from a firstconfiguration, shown in FIG. 72, to a second configuration, shown inFIG. 71. In one embodiment, the elongate body 5002 is movable from thefirst configuration to the second configuration when inserted within thepatient, as discussed above. In the first configuration, the accessdevice 5000 is configured, e.g., sized, for insertion into the patient.As discussed more fully below, in one embodiment, the passage 5014 has arelatively small transverse cross-sectional area at the distal end 5006of the first configuration of the access device 5000. For example, thepassage 5014 can have a cross-sectional area about equal to thecross-sectional area of the proximal end 5004, or less.

In the second configuration, the cross-sectional area of the passage5014 at the distal end 5006 is greater than the cross-sectional area ofthe passage 5014 at the proximal end 5004 in one embodiment. The secondconfiguration is particularly well suited for performing surgicalprocedures in the vicinity of a spinal location. Other configurationsand arrangements of the access device 5000 are discussed herein below.

As shown in FIGS. 67 and 68, in one embodiment, the proximal portion5010 and the distal portion 5012 are discrete, i.e., separate members.In other embodiments, the proximal and distal portions 5010, 5012 are aunitary member. In the illustrated embodiment, the proximal portion 5010comprises an oblong, generally oval shaped cross section over theelongated portion. It will be apparent to those of skill in the art thatthe cross section can be of any suitable oblong shape. The proximalportion 5010 can be any desired size. The proximal portion 5010 can havea cross-sectional area that varies from one end of the proximal portion5010 to another end. For example, the cross-sectional area of theproximal portion 5010 can increase or decrease along the length of theproximal portion 5010. Preferably, the proximal portion 5010 is sized toprovide sufficient space for inserting multiple surgical instrumentsthrough the elongate body 5002 to the surgical location. In oneembodiment, the cross-sectional area of the proximal portion 5010 canhave a generally elliptical shape. In some embodiments, the generallyelliptical shape can include generally straight side portions.

As shown in FIG. 67, the generally oval shaped cross section of theproximal portion 5010 in one embodiment has a first dimension 5026 ofabout 24 mm and a second dimension 5028 of about 35 mm. The first andsecond dimensions 5026, 5028 could range from at least about 10 mm up toabout 70 mm or more. The proximal portion 5010 in one embodiment has athird dimension 5030 of about 50 mm, but the third dimension 5030 couldrange from about 10 mm up to about 180 mm or more. In one embodiment,the proximal portion 5010 extends distally at least partially into thedistal portion 5012 of the device 5000, as shown in FIG. 70. In FIG. 67,the proximal portion 5010 extends a distance 5032 of about 10 mm intothe distal portion 5012. The proximal portion 5010 can extend a distance5032 of between about 5 mm and about 20 mm into the distal portion 5012in some embodiments. The exposed portion of the proximal portion 5010(e.g., the portion thereof that extends proximally of the distal portion5012) can be of any suitable height. Additionally, the distance 5032that the proximal portion 5010 extends into the distal portion 5012 canbe increased or decreased, as desired.

As shown in FIGS. 67 and 68, the proximal portion 5010 is coupled withthe distal portion 5012, e.g., with one or more couplers 5050. Theproximal and distal portions 5010, 5012 are coupled on a first lateralside 5062 and on a second lateral side 5064 with the couplers 5050 inone embodiment. When applied to a patient in a posterolateral procedure,either of the first or second lateral sides 5062, 5064 can be a medialside of the access device 5000, i.e., can be the side nearest to thepatient's spine. The couplers 5050 can be any suitable coupling devices,such as, for example, rivet attachments. In one embodiment, the couplers5050 are located on a central transverse plane of the access device5000.

The couplers 5050 preferably allow for at least one of rotation andpivotal movement of the proximal portion 5010 relative the distalportion 5012. A portion of the range of rotation and pivotal movement ofthe proximal portion 5010 relative the distal portion 5012 can be seenby comparing the position of the proximal portion 5010 in FIG. 67 to theposition thereof in FIG. 69. In FIG. 69, the proximal portion 5010 isseen at an angle α of about 20 degrees with respect to a transverseplane extending vertically through the couplers. One skilled in the artwill appreciate that rotating or pivoting the proximal portion 5010 tothe angle α permits enhanced visualization of and access to a differentportion of the spinal location accessible through the access device 5000than would be visualized and accessible at a different angle. Dependingon the size of the distal portion 5012, the angle α can be greater than,or less than, 20 degrees. Preferably, the angle α is between about 10and about 40 degrees.

The pivotable proximal portion 5010 allows for better access to thesurgical location and increased control of surgical instruments.Additionally, the generally oval shape of the proximal portion 5010 hasincreased the cross-sectional area available for a variety ofprocedures, some of which may require or benefit from more proximal endexposure. Embodiments having a generally oval shape can also be employedadvantageously in procedures such as the lateral or postero-lateralplacement of artificial disks, as well as other developing procedures.

As discussed above, the distal portion 5012 is expandable in oneembodiment. As shown in FIG. 70, the degree of expansion of the distalportion 5012 is determined by an amount of overlap between a first skirtmember 5034 and a second skirt member 5036 in one embodiment. Inparticular, the first skirt member 5034 has a first overlapping portion5090 on the first lateral side 5062 and the second skirt member 5036 hasa second overlapping portion 5092 on the first lateral side 5062. Thefirst skirt member 5034 has a third overlapping portion 5094 on thesecond lateral side 5064 and the second skirt member 5036 has a fourthoverlapping portion 5096 on the second lateral side 5064. The first andsecond overlapping portions 5090, 5092 overlap to define a first overlaparea 5098. The third and fourth overlapping portions 5094, 5096 overlapto define a second overlap area 5100. The extents of the first andsecond overlap areas 5098, 5100 preferably are reduced when the distalportion 5012 is in the second configuration. The extents of the firstand second overlap areas 5098, 5100 preferably are increased when thedistal portion 5012 is in the first configuration.

The distal portion 5012 preferably is manufactured from a rigidmaterial, such as stainless steel. The distal portion 5012 of the accessdevice 5000 can be manufactured from a sheet of stainless steel having athickness of between about 0.003-0.010 inches (0.076-0.254 mm). In someembodiments, the thickness is about 0.007 inches (0.178 mm). Nitinol,plastics, and other suitable materials can also be used.

In some embodiments, the distal portion 5012 can be manufactured so thatit normally assumes an expanded configuration. Additionally, the distalportion 5012 can assume an intermediate configuration and correspondingcross-sectional area, which has greater dimensions than the firstconfiguration, and smaller dimensions than the second configuration.Alternatively, an expander apparatus, similar to those previouslydiscussed herein, can be used to expand the distal portion 5012 asuitable amount.

The skirt members 5034, 5036 preferably are slidably coupled together.In one embodiment, the first and second skirt members 5034, 5036 areslidably coupled with each other with at least one guide member disposedin at least one slot defined in each of the skirt members 5034, 5036. Inparticular, a first slot 5102 is formed in the first overlapping portion5090 of the first skirt member 5034 and a second slot 5104 is formed inthe second overlapping portion 5092 of the second skirt member 5036 onthe first lateral side 5062 of the access device 5000. A guide member5106 extends through the first and second slots 5102, 5104 and istranslatable therein. Similarly, a third slot 5108 is formed in thethird overlapping portion 5094 of the first skirt member 5034 and afourth slot 5110 is formed in the fourth overlapping portion 5096 of thesecond skirt member 5036 on the second lateral side 5064 of the accessdevice 5000. A guide member 5112 extends through the third and fourthslots 5108, 5110 and is translatable therein.

Any suitable mechanism for slidably coupling the skirt members 5034,5036 can be used. In the illustrated embodiment, two floating rivets areused as guide members 5106, 5112. In another embodiment, one or more ofthe slots 5102, 5104, 5108, 5110 can include a locking or ratchetingmechanism (not shown). Locking mechanism is used in its ordinary sense(i.e. a mechanism to maintain relative positions of members) and is abroad term and it includes structures having detent arrangements,notches, and grooves. Some additional examples of locking mechanisms aredisclosed in U.S. patent application Ser. No. 10/361,887, filed Feb. 10,2003, entitled “Structure for Receiving Surgical Instruments,” publishedas application publication No. US2003/0153927 on Aug. 14, 2003, which ishereby incorporated by reference herein in its entirety.

With reference to FIGS. 67-72, as discussed above, the skirt members5034, 5036 preferably pivot about couplers 5050 joining the proximalportion 5010 with the distal portion 5012. The distal portion 5012preferably pivots on an axis perpendicular to the longitudinal axis ofthe access device 5000. This arrangement is particularly useful forproviding surgical access to anatomical features generally located andoriented along the Cephalad-Caudal direction.

As discussed above, the access device 5000 can be expanded from thefirst configuration to the second configuration by way of the movementof the first skirt member 5034 relative to the second skirt member 5036.In the illustrated embodiment, the distal portion 5012 is generally ovalshaped both in the first configuration, when the device 5000 isgenerally contracted, and in the second configuration, when the device5000 is generally expanded. However, the distal portion 5012 may beconfigured to transition from a generally circular cross-section distalend (or other convenient shape) in the first configuration to agenerally oval cross-section distal end in the second configuration.

As best seen in FIG. 72, the distal portion 5012 preferably has a firstdimension 5052 in the first configuration of approximately 24 mm and asecond dimension 5054 of approximately 35 mm. As best seen in FIG. 71,the distal portion 5012 preferably has a first dimension 5056 ofapproximately 45 mm and a second dimension 5058 of approximately 70 mmin the second configuration. Accordingly, in one embodiment in theexpanded configuration the distal portion 5012 opens distally toapproximately 45 mm by 70 mm. The distal portion 5012 can be arranged toopen more or less, as needed or desired. For example, the distal portion5012 can take on an oval shape wherein the second dimension 5058 islonger than 70 mm, e.g., about 85 mm or more. Alternatively, the distalportion 5012 can have a shape wherein the second dimension 5058 isshorter than 70 mm, e.g., about 45 mm or less. Similarly, in someembodiments the first dimension 5052 can be longer or shorter than 45mm, e.g., about 35 mm or about 55 mm. As shown in FIG. 67, the distalportion 5012 has a height 5060 that is approximately 45 mm. However, oneskilled in the art should recognize that the height 5060 of the distalportion 5012 can be any suitable height. The height 5060 preferably iswithin the range of about 20 mm to about 150 mm. Access devices havingrelatively shorter skirt heights 5060 may be advantageous for use withpatients having relatively less muscle tissue near the surgical locationand generally require smaller incisions. Access devices havingrelatively longer skirt height 5060 may be advantageous for use withpatients having relatively more muscle tissue near the surgicallocation, and may provide greater access.

The distal portion 5012 preferably is sufficiently rigid that it iscapable of displacing surrounding tissue as the distal portion 5012expands. Depending upon the resistance exerted by the surroundingtissue, the distal portion 5012 is sufficiently rigid to provide someresistance against the tissue to remain in the second, expandedconfiguration. Moreover, the second configuration is at least partiallysupported by the body tissue of the patient. The displaced tissue tendsto provide pressure distally on the distal portion 5012 to at leastpartially support the access device 5000 in the second configuration.The rigidity of the distal portion 5012 and the greater expansion at thedistal end 5006 creates a stable configuration that is at leasttemporarily stationary in the patient, which at least temporarily freesthe physician from the need to actively support the elongate body 5002.

Another advantageous aspect of the access device 5000 is illustratedwith reference to FIGS. 71 and 72. In particular, the elongate body 5002has a first location 5068 and a second location 5070. The first location5068 is distal of the second location 5070. The elongate body 5002 iscapable of having a configuration when inserted within the patientwherein the cross-sectional area of the passage 5014 at the firstlocation 5068 is greater than the cross-sectional area of the passage5014 at the second location 5070. The passage 5014 is capable of havingan oblong shaped cross section between the second location 5070 and theproximal end 5004.

In some embodiments the passage 5014 preferably is capable of having agenerally elliptical cross section between the second location 5070 andthe proximal end 5004. Additionally, the passage 5014 preferably iscapable of having a non-circular cross section between the secondlocation 5070 and the proximal end 5004. Additionally, in someembodiments, the cross section of the passage 5014 can be symmetricalabout a first axis 5072 and a second axis 5074, the first axis 5072being generally normal to the second axis 5074.

As shown in FIG. 71, the configuration of the elongate body 5002 betweenthe first location 5068 and the second location 5070 is generallyconical, when the elongate body 5002 is expanded within the patient. Theterm “conical” is used in its ordinary sense (i.e. a surface formed byline segments joining every point of the boundary of a closed base to acommon vertex) and is a broad term and it includes structures having agenerally oblong, or oval, cross section, as well as structures having asurface that extends only partially toward a vertex. In someembodiments, the first location 5068 can be near a distal end 5006 ofthe elongate body 5002, and the second location 5070 can be near aproximal end 5004 of the elongate body 5002.

In the illustrated embodiment, the elongate body 5002 has an oblongshaped cross section near its proximal end 5004 at least when theelongate body 5002 is in the second configuration. In some embodiments,the elongate body 5002 has an oblong shaped cross section alongsubstantially the entire length between the proximal end 5004 and thesecond location 5070.

Additionally, in some embodiments the passage 5014 can have a generallyoval shaped cross section between the second location 5070 and theproximal end 5004. The elongate body preferably has a generally ovalshaped cross section at its proximal end 5004 at least when the elongatebody 5002 is in the second configuration. The elongate body 5002 canhave a generally oval shaped cross section along substantially theentire length between the proximal end 5004 and the second location5070. The passage 5014 can also have a cross section between the secondlocation 5070 and the proximal end 5004 where the cross section isdefined by first and second generally parallel opposing side portions5076, 5078 and first and second generally arcuate opposing side portions5080, 5082.

In some embodiments, it is useful to provide a structure to maintain theaccess device 5000 in an un-expanded state until expansion of the deviceis desired. As shown in FIG. 73, in one embodiment an outer sleeve 5084,e.g., a plastic sleeve, is provided which surrounds the access device5000 and maintains the distal portion 5012 in the first configuration.The outer sleeve 5084 can be produced to function as previouslydescribed herein with reference to other embodiments. For example, theouter sleeve 5084 can have a braided polyester suture 5086 embeddedwithin it, aligned substantially along the longitudinal axis thereof,such that when the suture 5086 is withdrawn, the sleeve 5084 is torn,which allows the access device 5000 to expand, either resiliently ormechanically, from the first configuration to the second configuration.

In a method for accessing a surgical location within a patient an accessdevice, such as the access device 5000, is provided. As stated above,the elongate body 5002 is capable of having a first configuration sizedfor insertion into the patient. The elongate body 5002 is capable ofhaving a second configuration when expanded within the patient. In thesecond configuration, the cross-sectional area of the passage 5014 at afirst location 5068 is greater than the cross-sectional area of thepassage 5014 at a second location 5070. The first location 5068 isdistal to the second location 5070. The passage 5014 is capable ofhaving an oblong shaped cross section between the second location 5070and the proximal end 5004. The method comprises inserting the accessdevice 5000, in the first configuration, into the patient to thesurgical location and expanding the device to the second configuration.

The access device 5000 is inserted to a spinal location in some methods.As shown in FIG. 73, an oblong shaped dilator 5088 preferably isinserted into the patient prior to insertion of the access device 5000.In some applications, the access device 5000 may be inserted laterallyto the spinal location. In other applications, the device 5000 isinserted posterolaterally to the spinal location. In some applications,the device 5000 is inserted anteriorly to the spinal location. Thedevice 5000 preferably can be expanded in a cephalad-caudal direction ata spinal location.

With reference to FIG. 73, an early stage in one method involvesdetermining an access point in the skin of the patient to insert theaccess device 5000. An incision is made at the determined location. Insome cases, the incision is approximately 1″ to 2″ long. A guide wire(not shown) is introduced under fluoroscopic guidance through theincision and past the skin, fascia, and muscle to the approximatesurgical site. A series of oblong, or generally oval shaped, dilators isused to sequentially expand the incision to the desired widths, about 24mm by 35 mm for the illustrated embodiment, without damaging thestructure of surrounding tissue and muscles. In one technique, a firstoblong dilator is placed over the guide wire, which expands the opening.The guide wire is then subsequently removed. A second oblong dilatorthat is slightly larger than the first dilator is placed over the firstdilator, which expands the opening further. Once the second dilator isin place, the first dilator is subsequently removed. This process of (1)introducing a next-larger-sized dilator coaxially over the previousdilator and (2) subsequently removing the previous dilator when thenext-larger-sized dilator is in place continues until an opening of thedesired size is created in the skin, muscle, and subcutaneous tissue.For the illustrated embodiment, these dimensions are about 24 mm byabout 35 mm. (Other dimensions for the openings that are useful withsome embodiments in connection with spinal surgery range from about 20mm to about 50 mm, and still other dimensions are contemplated.) Inother techniques, a series of dilators having circular (or other shaped)cross-sections are used to partially dilate the opening. Then, a finaldilator having a circular inner diameter and an oblong or generally ovalshaped outer perimeter can be used to further dilate the opening.

As illustrated in FIG. 73, following placement of the largest oblong, orgenerally oval shaped dilator 5088, the access device 5000, in the firstconfiguration, is introduced and positioned in a surroundingrelationship over the dilator 5088. The dilator 5088 is subsequentlyremoved from the patient, and the access device 5000 is allowed toremain in position.

Once the access device 5000 is positioned in the patient, it can beenlarged to provide a passage 5014 for the insertion of various surgicalinstrumentation and an enlarged space for performing the proceduresdescribed herein. As described above, the elongate body 5002 canaccommodate the enlargement in several ways. In the illustratedembodiment, the distal portion 5012 of the device 5000 can be enlarged,and the proximal portion 5010 can maintain an oblong shape. The relativelengths of the proximal portion 5010 and the distal portion 5012 can beadjusted to vary the overall expansion of the access device 5000.Alternatively, in some embodiments expansion can extend along the entirelength of the elongate body 5002.

In the illustrated embodiment, the access device 5000 can be expanded byremoving the suture 5086 and tearing the sleeve 5084 surrounding theaccess device 5000, and subsequently expanding the distal portion 5012mechanically, or allowing the distal portion 5012 to resiliently expandtowards the expanded configuration, to create an enlarged surgicalspace. In some embodiments, the enlarged surgical space extends from theL4 to the S1 vertebrae.

The access device 5000 can be enlarged at its distal portion 5012 usingan expander apparatus to create a surgical access space. An expanderapparatus useful for enlarging the elongate body 5002 has a reducedprofile configuration and an enlarged configuration. Additionally, theexpander apparatus can have an oblong, or generally oval shape. Theexpander apparatus is inserted into the elongate body 5002 in thereduced profile configuration, and subsequently expanded to the enlargedconfiguration. The expansion of the expander apparatus also causes theelongate body 5002 to be expanded to the enlarged configuration. In someembodiments, the expander apparatus can increase the cross-sectionalarea of the elongate body 5002 along substantially its entire length. Inother embodiments, the expander apparatus expands only a distal portion5012 of the elongate body 5002, allowing a proximal portion 5010 tomaintain a constant oblong, or generally oval shape. Other expanderapparatus are disclosed in U.S. patent application Ser. No. 10/665,754,entitled “Surgical Tool for Use in Expanding a Cannula”, filed on Sep.19, 2003.

In addition to expanding the elongate member 5002, the expanderapparatus can also be used to position the distal portion 5012 of theelongate member 5002 at the desired location for the surgical procedurein a manner similar to that described previously with reference toanother embodiment.

Once the distal portion 5012 has expanded, the rigidity and resilientcharacteristics of the distal portion 5012 allow the elongate body 5002to resist closing to the first configuration and to at least temporarilyresist being expelled from the incision. These characteristics create astable configuration for the elongate body 5002 to remain in position inthe body, supported by the surrounding tissue.

The access device 5000, like the other access devices described herein,has a wide variety of applications wherein the passage 5014 providesaccess to one or more surgical instruments for performing a surgicalprocedure. In one application, the passage 5014 provides access toperform a two level posterolateral fixation of the spine involving theL4, L5 and S1 vertebrae. The access devices 5000 can be used to delivera wide variety of fixation elements, including rigid, semi-rigid, ordynamic fixation elements. The access devices are not limited to theposterolateral approach nor to the L4, L5 and S1 vertebrae. The accessdevices may be applied in other anatomical approaches and with othervertebrae within the cervical, thoracic and lumbar spine. The accessdevices can be applied in procedures involving one or more vertebrallevels and in anterior and lateral procedures. Further procedures inwhich the access devices described herein can be applied includeprocedures involving orthobiologics, bone morphogenetic proteins, andblood concentrators. The access devices can also be used with proceduresinvolving prosthetics, such as disc nucleus replacement, facet jointreplacement, or total disc replacement. The access devices can also beapplied in procedures involving vertebroplasty, where a crushed vertebrais brought back to its normal height.

The access devices described herein also can be used in connection withinterbody fusion, and fusion of the facets and transverse processes.Some of the fusion procedures that can be performed via the accessdevices described herein employ allograft struts, bone filling material(e.g., autograft, allograft or synthetic bone filling material), andcages and/or spacers. The cages and the spacers can be made of metal, apolymeric material, a composite material, or any other suitablematerial. The struts, cages, and spacers are used in the interbody spacewhile the bone filling material can be used both interbody andposterolaterally. Any of the foregoing or other fusion procedures can beused in combination with the orthobiologics and can be performed via theaccess devices described herein.

Some examples of uses of the access devices described in otherprocedures and processes, as well as further modifications andassemblies, are disclosed in U.S. patent application Ser. No.10/845,389, filed May 13, 2004, entitled “Access Device For MinimallyInvasive Surgery,” and in U.S. patent application Ser. No. 10/658,736,filed Sep. 9, 2003 which are hereby incorporated by reference herein intheir entireties.

FIGS. 74-79 illustrate embodiments having lighting elements. FIGS. 74-76illustrate one embodiment of a lighting element 5120 coupled with asupport arm 5122 compatible with an access device 5124 having a proximalportion with a generally circular cross section. In other embodiments,support arms can be configured to be coupled with access devices havingproximal portions with generally oblong or oval cross sections.

The support arm 5122 preferably is coupled with the access device 5124to provide support for the access device 5124 during a procedure. Asshown in FIGS. 74 and 75, the support arm 5122 comprises a pneumaticelement 5126 for maintaining the support arm 5122 in a desired position.Depressing a button 5128 coupled with a valve of the pneumatic element5126 releases pressure and allows the support arm 5122 and access device5124 to be moved relative the patient 5130. Releasing the button 5128 ofthe pneumatic element 5126 increases pressure and maintains the accessdevice 5124 and support arm 5122 in the desired position. The supportarm 5122, as shown, is configured for use with a mechanical arm usingsuction, or a vacuum to maintain the access device in a desiredlocation. One of skill in the art will recognize that various othersupport arms and mechanical arms can be used. For example, commerciallyavailable mechanical arms having clamping mechanisms can be used as wellas suction or pressure based arms.

As shown in FIGS. 74-76, the support arm 5122 can comprise an inner ringportion 5132 and an outer ring portion 5134 for surrounding the accessdevice 5124 at its proximal end. In the illustrated embodiment, theinner and outer ring portions 5132, 5134 are fixed relative each other.In other embodiments the inner and outer ring portions 5132, 5134 canmove relative each other. The support arm 5122 preferably comprises alighting element support portion 5136. In the illustrated embodiment,the lighting element support portion 5136 extends above upper surfacesof the inner and outer ring portions 5132, 5134. The lighting elementsupport portion 5136 can extend from the inner ring portion 5132, theouter ring portion 5134, or both. The lighting element support portion5136 can have a notch or groove 5138 for receiving and supporting thelighting element 5120. Additionally, the lighting element supportportion 5136 can have one or more prongs extending at least partiallyover the lighting element 5120 to hold it in place.

In the illustrated embodiment, the lighting element 5120 has anelongated proximal portion 5140 and a curved distal portion 5142. Theproximal portion 5140 of the lighting element 5120 preferably is coupledwith a light source (not shown). The curved distal portion of thelighting element 5120 in one embodiment extends only a short distanceinto the access device and is configured to direct light from the lightsource down into the access device 5124. In another embodiment, thelighting element 5120 can be provided such that it does not extend intothe access device. In such an embodiment, the right portions 5132 and5134 only partially surround the proximal end of the access device 5124.Providing a lighting element 5120 for use with the access device 5124preferably allows a user to see down into the access device 5124 to viewa surgical location. Accordingly, use of a lighting element 5120 can, insome cases, enable the user to perform a procedure, in whole or in part,without the use of an endoscope. In one embodiment, the lighting element5120 enables a surgeon to perform the procedure with the use ofmicroscopes or loupes.

FIGS. 74-79 illustrate other embodiments of lighting elements. As shownin FIG. 77, a lighting element 5160 comprises a support member 5162, anaccess device insert 5164, and fiber optic elements 5166. The supportmember 5162 has a proximal end 5168, a central portion 5170, and adistal end 5172. The proximal end 5168 preferably has a coupling portion5174 for coupling the support member 5162 to a support arm or othersupport system (not shown). The central portion 5170 preferably iscoupled with the fiber optic elements 5166 to provide support there to.The distal end 5172 preferably is coupled with the access device insert5164.

In the illustrated embodiment, the access device insert 5164 isconfigured to be inserted in an access device having a proximal portionwith a generally circular cross section. The access device insert 5164is coupled with the fiber optic elements 5166. The fiber optic elements5166 extend down into the access device insert 5164 so that the ends ofthe fiber optic elements 5166 can direct light down inside an accessdevice along side portions there of.

FIGS. 78 and 79 illustrate other embodiments of lighting elementssimilar to the embodiment described with reference to FIG. 77.Components of the lighting elements shown in FIGS. 108 and 109 that weredescribed with reference to FIG. 77 are given the same referencenumerals that were used in FIG. 77, except that an “a” is added in FIG.78 and a “b” is added in FIG. 79. As shown in FIGS. 78 and 79, accessdevice inserts 5164 a, 5164 b are configured to be inserted into accessdevices having proximal portions with generally oblong, or oval, crosssections. As shown in FIG. 78, the access device insert 5164 a has agenerally oblong or oval shaped cross section. The access device insert5164 a is coupled with the fiber optic elements 5166 a along a longerside surface of the access device insert 5164 a. As shown in FIG. 79,the access device insert 5164 b has a generally oblong or oval shapedcross section. The access device insert 5164 b is coupled with the fiberoptic elements 5166 b along a shorter side surface of the access deviceinsert 5164 b. Use of an illumination element with an expandable accessdevice having an oblong shaped proximal section, in some cases, allows adoctor to perform procedures that would be difficult to perform using anendoscope. Increased visualization of the surgical location through theaccess device can simplify some procedures. For example, decompressionof the contra-lateral side can be achieved more easily in some caseswithout the use of an endoscope.

FIGS. 80 and 81 show an access assembly 6000 that can be incorporatedinto a surgical system, such as the system 10. The access assembly 6000includes an access device or retractor 6010 coupled with a mount fixture6014. The mount fixture 6014 may be coupled with a support arm, such asthose discussed above. The access device 6010 preferably is providedwith an oblong transverse cross-section near the proximal end thereof,which can be coupled with the mount fixture 6014. More preferably, theaccess device 6010 can be provided with an oval transverse cross-sectionin some embodiments. The cross section can be generally elliptical insome embodiments. The oblong shaped cross-section of the access device6010 is particularly beneficial for surgical procedures (such as twolevel pedicle screw fixation) that are performed at an elongatedsurgical field. Also coupled with the mount fixture 6014 is a guidefixture 6016. In one embodiment, the guide fixture 6016 is configured tobe coupled with a viewing element 6018, such as any of those discussedherein, or any other suitable viewing element.

The mount fixture 6014 and the guide fixture 6016 advantageously areconfigured to introduce the viewing element 6018 into the access device6010 at discrete locations. In the illustrated embodiment, the mountfixture 6014 and the guide fixture 6016 are configured to enable aviewing element to be positioned at four discrete locations that arelocated at opposite corners of the elongated mount fixture 6014. In theillustrated embodiment, a plurality of holes 6022 (e.g., two holes) isprovided at each of four corners on the top surface of the mount fixture6014. Each of the holes 6022 is configured to receive a pin that extendsfrom the lower surface of the guide fixture 6016. The engagement of thepins in the holes 6022 is such that the guide fixture 6016 is securelycoupled with the mount fixture 6014 so that the guide fixture 6016 willnot be dislodged inadvertently during a procedure. However, theengagement of the pins in the holes 6022 also is such that a user of theaccess assembly 6000 can disengage the guide fixture 6016 and theviewing element 6018 and reposition it at any of the other discretelocations during a procedure. Although the coupling of the mount fixture6014 and the guide fixture 6016 is illustrated as a two hole-two pinarrangement, other arrangements are possible and contemplated. Forexample, more or less than two holes and pins, couplers of other shapes(e.g., pins and holes of different shapes, tongues and slots, etc.), andclamp devices could be used in place of or in combination with theillustrated two hole-two pin arrangement.

FIG. 82 shows one embodiment of the access device 6010 that is similarto those hereinbefore described, except as set forth below. The accessdevice 6010 has an elongate body with a distal portion 6028 and aproximal portion 6032. Each of the distal and proximal portions 6028,6032 defines a portion of a passage that extends through the accessdevice 6010. In some embodiments, the distal portion 6028 of the accessdevice 6010 is shorter compared to the distal portion of some of theother access devices described herein. In particular, the distal portion6028 is configured such that when the access device 6010 is applied tothe patient, the distal portion 6028 is completely or substantiallycompletely beneath the skin, as discussed below. This arrangement isadvantageous in that the access device 6010 does not need to furtherdilate the incision at the skin.

Although the illustrated embodiment of the access device 6010 has twodiscrete portions that are coupled in a suitable manner, other accessdevices embodying features discussed herein can be configured withoutmultiple, discrete portions. Both the proximal and distal portionspreferably are made from a rigid, radiolucent material that is visibleunder fluoroscopy. The distal and proximal portions 6028, 6032preferably both have sufficient strength or stiffness to retract tissue,though the strength or stiffness of the proximal and distal portionsneed not be the same. Examples of materials that may be used and otherfeatures that can be incorporated into the access device 6010 arediscussed above and in the patents and applications incorporated byreference herein.

The proximal portion 6032 preferably is elongated and has a length alonga longitudinal axis 6036 that is selected based upon the anatomy (e.g.,the portion of the spine) being treated. The length of the proximalportion 6032, and other aspects of the access device 6010, also can bebased in part on the individual patient's anatomy, e.g., on the amountof tissue between the skin and the surgical location, which variesacross the patient population.

As discussed above, the configuration of at least a portion of theproximal portion 6032 is elongated in at least one direction in a planeperpendicular to the axis 6036. One advantageous arrangement of theproximal portion 6032 provides an oblong transverse cross-section.Another advantageous arrangement provides an oval transversecross-section. The configuration of the proximal portion 6032 isillustrated in FIGS. 85-86A, which show that the transversecross-section of the proximal portion 6032 is elongated along a line6040. As will be discussed in more detail below, the line 6040 extendsalong the main axis of expansion of the access device 6010.

There are several advantages to configuring the proximal portion 6032with an oblong transverse cross-section. Many bone and joint procedures,particularly spine procedures, are performed at elongated surgicalfields. For example, multi-level procedures may be much more convenientfor the surgeon and beneficial for the patient if access can be providedto at least a portion of three or more adjacent vertebrae. Whilesymmetrical access could be provided to three or more adjacentvertebrae, much non-adjacent tissue (i.e., tissue not in the immediatevicinity of the structures being treated) would be disrupted, causinggreater trauma to treat the patient than necessary. This additionaltrauma approaches that of open surgery as the length of the surgicalfield increases. In contrast, the use of an oblong transversecross-section proximal portion 6032 and access device 6010 lessens, ifnot minimizes, the amount of non-adjacent tissue that is disrupted.Oblong access from a posterior or posterolateral approach isparticularly advantageous in that it provides access to anatomy for awide variety or procedures, e.g., those that affect the pedicles.

The distal portion 6028 also extends along the longitudinal axis 6036and comprises a first overlapping portion 6050 and a second overlappingportion 6054. The first overlapping portion 6050 extends between aproximal end 6058 and a distal end 6062 of the distal portion 6028. Thesecond overlapping portion 6054 extends between the proximal end 6058and the distal end 6062 of the distal portion 6028. The overlappingportions 6050, 6054 overlap each other to create an enclosed space 6066therebetween. In one embodiment, each of the overlapping portions 6050,6054 extends along the axis 6036 when the overlapping portions arecoupled with the proximal portion 6032 and is formed from a thin, rigidmaterial (such as sheet metal) that is curled into a generally U-shapedstructure.

The first and second overlapping portions 6050, 6054 are coupled in amanner that permits expansion of the distal portion 6028 at the distalend 6062. The advantages of being able to expand the distal portion arediscussed above. The first and second overlapping portions 6050, 6054also are configured to be selectively locked or unlocked in one or morestates of expansion or contraction. Further advantages of the lockingaspect of the first and second overlapping portions 6050, 6054 arediscussed below.

In one embodiment, the distal portion 6028 has a slot and guide memberarrangement that enables expansion of the distal portion 6028.Corresponding arcuate slots 6070 a, 6070 b are formed in the firstoverlapping portion 6050 and the second overlapping portion 6054,respectively. In one embodiment, a guide member, such as a sliding rivet6074, extends through the corresponding slots 6070 a, 6070 b therebycoupling the slots. The slots 6070 a, 6070 b and the rivet 6074 enablethe distal portion 6028 to be expanded by allowing the rivet 6074 toslide along the slots as the overlapping portions 6050, 6054 move awayfrom or toward each other. In the illustrated embodiment, a second pairof slots and a corresponding guide member (e.g., a rivet) are providedon the opposite side of the access device 6010 from the slots 6070 a,6070 b and the rivet 6074. Thus, two rivets 6074 are provided incorresponding pairs of slots adjacent each edge of the overlappingsections 6050, 6054. This arrangement enables generally linear expansionof the distal portion 6028 along and parallel to a vertical planeextending along the long dimension of the proximal portion 6032 andcontaining the line 6040. Another arrangement provides one or more slotson only one side of the access device 6010, which would provide a moremulti-directional expansion (e.g., both cephalad-caudad andmedial-lateral) near the distal end 6062 of the distal portion 6028.

The distal portion 6028 is configured to be actuatable from anon-expanded configuration to an expanded configuration. Thenon-expanded configuration is said to be “low-profile” in that thetransverse cross-section of the distal portion 6028, particularly at thedistal end 6062, is relatively small. The access device 6010, like theother access devices described herein, is configured to be inserted overa dilating structure, such as a dilator or an obturator. One suitabledilator is described below in connection with FIGS. 120-122. Providing alow-profile distal end 6062 in the non-expanded configuration enables agenerally smaller dilating structure to be used, reducing the amount oftrauma to the patient during insertion. In one embodiment the distalportion 6028 has an oblong cross-section similar to that of the proximalportion 6032 when the distal portion 6028 is in a low profileconfiguration. The transverse cross-section of the distal portion 6028in the low profile configuration need not be constant from the distalend 6058 to the proximal end 6062 thereof. For example, in oneembodiment the transverse cross-section of the distal portion 6028transitions from generally circular near the distal end 6058 togenerally oblong near the proximal end 6062 (e.g., generally matchingthe transverse cross-section of the proximal portion 6062 at the distalend thereof). The distal portion 6028 may also be arranged to transitionfrom a circular cross-section configuration to a non-circularcross-section configuration.

The distal portion 6028 also is provided with a lock 6090 that enables auser to selectively lock the distal portion 6028 into one or more statesof expansion. The lock 6090 can take many forms. In one embodiment, thelock 6090 includes a slot 6094 and an L-shaped flange 6098 that can bemoved (e.g., rotated) into and out of the slot 6094.

In one embodiment, the slot 6094 extends generally perpendicularly fromthe slot 6070 a and the slot 6094 has a first side 6094 a and a secondside 6094 b. Each of the first and second sides 6094 a, 6094 b of theslot 6094 restrains relative movement of the overlapping portions 6050,6054 to selectively limit expansion or un-expansion of the distalportion 6028 when the lock 6090 is engaged.

In one embodiment, the L-shaped flange 6098 includes an elongated planarportion 6502 and a lock tab 6506. The elongated portion 6502 preferablyis relatively thin so that it may reside between the overlappingportions 6050, 6054. In one embodiment, the elongated portion 6502 isrotatably coupled (e.g., with a pin or a portion of a rivet, e.g., ahalf-rivet) with the overlapping portion 6054 near one edge thereof. Theelongate portion 6502 is thereby enabled to swing about an arc. In oneembodiment, the lock tab 6506 extends generally perpendicularly from theend of the elongated portion 6502 that is opposite the rotatably coupledend. The length of the lock tab 6506 is greater than the thickness ofthe first overlapping portion 6050. In one embodiment, the lock tab 6506extends far enough beyond the first overlapping portion 6050 into thearea defined within the access device 6010 to enable a user to engageand manipulate the lock tab 6506 in the enclosed space 6066. Where theaccess device 6010 is to be inserted over a dilating structure, the locktab 6506 preferably is configured to not interfere with the dilatingstructure. For example, the lock tab 6506 can be made short enough sothat the lock tab 6506 does not extend far enough into the enclosedspace 6066 defined inside the access device 6010 to interfere with thedilating structure. Any suitable tool may be used to articulate the lock6090, e.g., by engaging and manipulating the lock tab 6506. For example,a tool that is long enough to extend from a location proximal of theproximal end of the proximal portion 6032 to the location of the lock6090 could be used. A number of conventional tools can be configured inthis manner, including a cobb elevator, a penfield, and a nerve hook.

In one application, the access device 6010 is used to provide minimallyinvasive access to the spine for a spinal procedure, such as a one-levelor a multi-level procedure. The patient is positioned prone on aradiolucent table and draped for posterior spinal surgery. The locationof the spine anatomy to be treated is identified, e.g., via fluoroscopy.In one technique, the location of adjacent pedicles on one side of themid-line of the spine are identified. Thereafter, an incision is madethrough the skin above the adjacent pedicles. In one technique, anincision of about 30-40 mm in length is made between two adjacentpedicles where a single level procedure (one involving two adjacentvertebrae) is to be performed. In another technique where a two-levelprocedure (one involving three vertebrae) is to be performed, anincision of 40-50 mm in length is made. As discussed above, in someembodiments, the access device 6010 is configured to be applied suchthat the distal portion 6028 is completely or substantially completelysubmerged beneath the skin. In one technique, an incision of about 30 mmis made in the skin so that an access device configured to be applied inthis manner may be applied to the patient. In some embodiments of theaccess devices described herein, a proximal portion thereof isconfigured to be expandable. In some techniques for applying accessdevices with expandable proximal portions, a larger incision may be madeto accommodate all or substantially all of the expansion of the proximalportion.

Thereafter a dilating structure, such as a series of dilators or anobturator, is inserted into the incision to enlarge the incision. It maybe desirable to use round or oblong dilators. Preferably the lastdilator has an outer profile that matches the un-expanded inner profileof the access device 6010. In one technique for a single levelprocedure, a 5 mm dilator is first inserted through the skin near thecenter of the skin incision and is docked on the lateral aspect of thesuperior facet. In a two-level procedure, a 5 mm dilator is firstadvanced through the skin near the center of the incision and is dockedon the mamillo-accessory ridge of the middle pedicle. Placement of the 5mm dilator may be verified by fluoroscopy. Subsequently, progressivelylarger dilators are inserted over each other. After a larger dilator isinserted, the next-smaller dilator is normally removed. One or more ofthe dilators, a cobb device, or even one of the surgeon's fingers mayalso be used to probe and to dissect soft tissue to ease expansion ofthe access device 6010, as discussed below. Placement of the finaldilator may be verified by fluoroscopy. Other procedures employ similardilating techniques by initially approaching other anatomical featureson or near the spine.

Thereafter, the access device 6010 is advanced to the anatomy to betreated. As discussed above, a sleeve deployable by a string may beemployed to maintain the access device 6010 in the low-profileconfiguration (e.g., in the un-expanded state) until the access deviceis in place. Various embodiments of the sleeve and string are discussedherein, e.g., in connection with FIGS. 123-124. In one technique, theassembly of the access device 6010, the sleeve, and the string isinserted into the incision and positioned so that the string faces themid-line of the spine. Thereafter the string is withdrawn, releasing thesleeve from the access device 6010. In particular, in one technique, thestring is pulled from near the proximal end of the access device 6010.This action causes the sleeve to be torn along a line extendingproximally from the distal end of the sleeve. The sleeve may bepartially or completely torn from distal to proximal, releasing at leastthe distal end of the access device 6010 for expansion. After the sleeveis released from the access device 6010, the access device 6010 is freeto expand and to be expanded.

FIG. 83B shows that prior to and during expansion of the access device6010, the L-shaped flange 6098 is positioned so that the lock tab 6506is located in the arcuate slot 6070 a. The lock tab 6506 has a thicknessthat is less than the proximal to distal width of the slot 6070 a sothat the lock tab 6506 can translate along the slot 6070 a betweenpositions corresponding to the un-expanded and expanded configurationsof the access device 6010. The access device 6010 may resiliently expandwith the lock tab 6095 in the slot 6070 a. Further expansion of theaccess device 6010 may be achieved by inserting and articulating anexpander tool, such as the expander tool 200 discussed above. Theexpansion and location of the access device 6010 may be confirmed byfluoroscopy.

After the access device 6010 has been fully expanded, the lock 6090 maybe articulated to lock the access device 6010 in the expandedconfiguration. In particular, the lock tab 6098 may be positioned in theslot 6094. As discussed above, the lock tab 6098 is pivotable at the endopposite the lock tab 6506. In one procedure, the user grasps androtates the lock tab 6506 from the expansion position in the slot 6070 ato the locked position in the slot 6094. As discussed above, the lock6090 may be manipulated in any convenient manner, e.g., by any suitabletool, as discussed above. FIG. 83B shows an arrow 6510 that indicatesthe rotation of the lock tab 6098 to the locked position. When in thelocked position, the lock tab 6098 may engage one of the sides 6094 a,6094 b of the slot 6094 to prevent either inadvertent further expansionor un-expansion of the access device 6010.

In one variation, another slot analogous to the slot 6094 is provided atthe opposite end of the arcuate slot 6070 a to enable the access device6010 to be locked in the un-expanded configuration. This arrangement andvariations thereof may substitute for the sleeve and string arrangement,discussed above.

After the access device 6010 is locked in position, various proceduresmay be performed on the spine (or other joint or bone segment). Asdiscussed above, these procedures may be performed with much less traumathan that associated with open surgery. After the procedures arecomplete, the access device 6010 may be un-expanded by articulating thelock 6090 from the locked position to the unlocked position, e.g., bymoving the lock tab 6098 from the slot 6094 to the slot 6070 a, whereinit is free to translate. FIG. 83A shows an arrow 6514 that indicates therotation of the lock tab 6098 to the unlocked position.

FIG. 84 shows an arrow 6518 that indicates un-expansion of the accessdevice 6010 after the procedure is complete.

FIGS. 87-150 illustrate and describe systems, devices, components, andmethods according to some additional embodiments. Details shown ordescribed in FIGS. 87-150 are merely representative of some preferredembodiments and are not intended to limit other embodiments. Some of thesystems, devices, components, and methods shown are similar to thosedescribed above or in the documents incorporated by reference herein.Additional features and advantages of the illustrated embodiments willbe apparent to those of ordinary skill in the art in view of thedisclosure herein.

FIGS. 87-122 illustrate instrumentation, systems, devices, components,and methods according to some embodiments. FIGS. 87-122 illustrateportions of support arms, light post mounts, visualization mounts, lightposts, visualization elements, indexing collar assemblies, and dilators,according to some embodiments. These devices and components cancooperate with access devices in access systems, such as those describedand shown herein to facilitate various surgical procedures.

FIGS. 87-119 illustrate portions of a visualization assembly 7000. Thevisualization assembly 7000 preferably is configured to be coupled witha proximal portion of an access device. In the illustrated embodiment,the visualization assembly 7000 is configured to be coupled with anaccess device having a proximal portion with an oval shapedcross-sectional area. In other embodiments, the visualization assembly7000 can be configured to be coupled with a proximal portion of anaccess device having any other oblong shaped or circular shaped (assuggested in FIG. 102) cross-sectional area. In one embodiment, thevisualization assembly 7000 is configured to be coupled with an accessdevice having a proximal portion that has a generally oval shapedopening that is about 24 mm wide and about 30 mm long. In anotherembodiment, the visualization assembly can be configured to be coupledwith an access device having a proximal portion with a generally ovalshaped opening that is about 24 mm wide and about 35 mm long.

FIGS. 87 and 88 show a visualization assembly 7000 that is similar tothe other visualization assemblies described herein, except as set forthbelow. With reference to FIGS. 87 and 88, the visualization assembly7000 has a light post mount 7002. In other embodiments, other suitablevisualization element mounts can be used. The light post mount 7002 hasa distal portion 7004 and a proximal portion 7006. The distal portion7004 has a generally oval shaped mounting portion 7008. In otherembodiments, the distal portion 7004 can have any other oblong shaped orcircular shaped mounting portion 7008. A light post assembly 7010 (seeFIGS. 98-99) preferably can be supported on a mounting portion 7008 ofthe light post mount 7002. The mounting portion 7008 has an outsidesurface 7012 and an inside surface 7014. The inside surface 7014preferably defines an oblong shaped opening 7016 to provide access to apassage of an access device. In the illustrated embodiment, the insidesurface 7014 defines a generally oval shaped opening 7016.

FIGS. 89-94 show a viewing element support mount that is similar to theother viewing element support mounts described herein, except as setforth below. With reference to FIGS. 89-94, the light post mount 7002has a ledge 7018 on the inside surface 7014 of the light post mount7002. The ledge 7018 preferably is configured so that the light postmount 7002 can rest on a top surface, a top edge, or an end of aproximal portion of an access device. The inside surface 7014 of thelight post mount 7002, below the ledge 7018, can extend over a proximalportion of an access device. The mounting portion 7008 preferably hasopenings 7020, such as, for example, holes or slots, defined in the wallof the mounting portion 7008 for supporting the light post assembly 7010or other visualization tool. As shown in the illustrated embodiment, themounting portion 7008 preferably is configured to receive the light postassembly 7010 at a plurality of locations or positions.

The light post mount 7002 has a support arm 7022 extending proximallyfrom the mounting portion 7008. With reference to FIGS. 87 and 88, thesupport arm 7022 preferably is coupled with an arm extension assembly7024 via an arm locking screw 7026. With reference to FIG. 89, the lightpost mount 7002 has a spline ring 7028 at a proximal portion 7006 of thesupport arm 7022. The spline ring 7028 preferably is configured forcoupling the light post mount 7002 with the arm extension assembly 7024via the arm locking screw 7026.

With reference to FIGS. 95-97, the spline ring 7028 has a spline portion7030 and an anchor portion 7032. The spline portion 7030 preferablycomprises a plurality of notches 7034 formed in a first surface 7036 ofthe spline portion 7030 to interface with the arm extension assembly7024 via the arm locking screw 7026. The anchor portion 7032 of thespline ring 7028 extends from a second surface 7038 of the splineportion 7030 generally opposite the spline surface 7036. The anchorportion 7032 and spline portion 7030 define an opening 7040 extendingthrough the spline ring 7028. The anchor portion 7032 can be insertedinto an opening 7042 (see FIGS. 90 and 93) in the light post mount 7002and preferably is secured therein using an epoxy.

FIGS. 98-99 show a viewing element that is similar to the other viewingelements described herein, except as set forth below. With reference toFIGS. 98-99, a light post assembly 7010 preferably comprises a lighttube 7044, a light post mount block 7046, and one or more locator pins7048. The light post assembly 7010 preferably is configured to becoupled with the light post support mount 7002. The light post assembly7010 has a coupler 7050 for connecting the light post assembly 7010 to alight source (not shown). The light tube 7044 preferably is angled todirect light down into a channel or passage of an access device when thelight post assembly 7010 is supported on the light post support mount7002. The light tube 7044 in the illustrated embodiment is about 3 mm indiameter and about 15 mm long. A longer light tube 7044 may be usedwhere it is desired to locate the end 7052 of the light tube 7044farther distally in an access device.

FIGS. 100-106 show a viewing element support block that is similar tothe other viewing element support blocks described herein, except as setforth below. With reference to FIGS. 100-106, the light post mount block7046 is configured to receive and support the light tube 7044, or otherviewing element. In one embodiment, the light post mount block 7046 hasan upper surface 7054 that is contoured for receiving the light tube7044. The light post mount block 7046 can have one or more openings 7056for receiving one or more locator pins 7048. The light post mount block7046 has a notched portion 7058 including a first surface 7060 forcontacting a top surface 7064 (see FIG. 89) of the light post mount 7002and a second surface 7062 for contacting a side surface 7066 of thelight post mount 7002. FIG. 107 shows one embodiment of a locator pin7048. The locator pin 7048 is generally cylindrical, though other shapesmay be used in some embodiments. The locator pin 7048 can be coupledwith the light post mount block 7046 to retain the light post mountassembly 7010 in a desired location on the light post mount 7002.

FIGS. 108-109 show an indexing collar assembly that is similar to theother indexing collar assemblies described herein, except as set forthbelow. With reference to FIGS. 108-109, one embodiment of an indexingcollar assembly 7068 comprises an indexing collar 7070, as shown in moredetail in FIGS. 110-119. The indexing collar assembly 7068 alsopreferably comprises a support arm 7072 or clamp arm, an arm extensionassembly 7074, and an arm locking screw 7076. In the illustratedembodiment, the indexing collar 7070 is configured to be coupled with anaccess device having a proximal portion with a generally oval shapedcross-sectional area. In other embodiments, the indexing collar 7070 canbe configured to be coupled with an access device having any otheroblong shaped cross-sectional area. In one embodiment, the indexingcollar 7070 is configured to be coupled with an access device having aproximal portion that has a generally oval shaped opening that is about24 mm wide and about 30 mm long. In another embodiment, the indexingcollar 7070 is configured to be coupled with an access device having aproximal portion with a generally oval shaped opening that is about 24mm wide and about 35 mm long.

FIGS. 108-119 show an indexing collar that is similar to the otherindexing collars described herein, except as set forth below. Withreference to FIGS. 108-119, in one embodiment, the support arm 7072 iscoupled with an indexing collar 7070, which can be configured to bereceived in a central opening of a base of an endoscope mount platformor other viewing element mount platform, such as shown in FIGS. 20-23.The indexing collar 7070 has an outer peripheral wall surface 7078, aninner wall surface 7080, and a wall thickness 7082 that is the distancebetween the wall surfaces. With reference to FIG. 119, the outerperipheral wall surface 7078 has a generally constant diameter. Theinner wall surface 7080 preferably has a variable diameter resulting ina generally oval shaped cross-sectional area defined by the inner wallsurface 7080. In other embodiments, the inner wall surface 7080 candefine any other oblong shaped cross-sectional area. Accordingly, thewall thickness 7082 varies between the outer peripheral wall surface7078 and the inner wall surface 7080.

In one embodiment, access devices of different shapes and dimensions canbe supported by providing indexing collars to accommodate each accessdevice size while using a single endoscope mount platform. The centralopening of the endoscope mount platform can have a constant dimension,e.g., a diameter of about 1.28 inches (32.5 mm). An appropriate indexingcollar is selected, e.g., one that is appropriately sized to support aselected access device. Thus, the outer wall and the outer diameterpreferably are unchanged between different indexing collars, althoughthe inner wall and the inner diameters of the oval shape can vary toaccommodate differently sized access devices.

The indexing collar 7070 can be positioned at or rested on a proximalportion of an access device to allow angular movement of the endoscopemount platform, or other viewing element mount platform, with respectthereto about the longitudinal axis. In one embodiment, the outer wallof the indexing collar 7070 includes a plurality of hemisphericalrecesses, or through holes 7084, that can receive one or more ballplungers on the endoscope mount platform. This arrangement permits theendoscope mount platform, along with an endoscope, or other viewingelement, to be fixed in a plurality of discrete angular positionsrelative the indexing collar 7070.

FIGS. 120-122 show a dilation element that is similar to the otherdilation elements described herein, except as set forth below. FIGS.120-122 illustrate one embodiment of a dilating structure or tool foruse with an access device. As shown in the illustrated embodiment, acannulated oval dilator 7086 can have an inner surface 7088 that has agenerally circular cross section and an outer surface 7090 that has agenerally oval shaped cross section. In other embodiments, the outersurface 7090 can have any other oblong shaped cross section. The outersurface 7090 preferably provides indications 7092 regarding instrumentdepth. In one embodiment, a proximal portion 7094 of the dilator 7086comprises a gripping portion 7096 to facilitate handling and to aid inthe insertion of the dilator 7086 into a patient. The gripping portion7096 of the dilator 7086, in some embodiments, can have, for example,raised portions or a knurled surface. The dilator 7086 preferably has atapered distal portion.

FIGS. 123-150 illustrate some embodiments of access devices, accessassemblies, and portions of access devices. FIGS. 123-150 show accessdevices that are similar to the other access devices described herein,except as set forth below. With reference to FIGS. 123-124, oneembodiment of an access device 7100 can be positioned in a low-profileconfiguration for insertion into a patient. As shown in FIGS. 123-124,the access device 7100 has a passage 7102 with a generally oval shapedcross section. In one embodiment, the cross section of a proximalportion 7104 of the passage 7102 preferably has a width of about 24 mmand a length of about 30 mm. The cross section of the passage 7102 atthe distal portion 7106 of the access device 7100, in the low profileconfiguration, preferably has a width of about 24 mm and a length ofabout 30 mm. The access device 7100 can be held in a low profileposition using a sleeve 7108 or a length of shrink tubing. A pull string7110 and tab 7112 can be used to at least partially release the shrinktubing from the access device 7100.

FIGS. 125-126 show the access device 7100 in an expanded configuration.In the illustrated embodiment, the access device 7100 has a distalportion 7106 that expands to a cross section at or near the distal endhaving a width of about 24 mm and a length of about 50 mm. In otherembodiments, the sizes and lengths associated with the access device7100 can vary, as will be described further below. The length 7128 ofthe access device 7100 from the proximal end of the proximal portion7104 to the distal end of the distal portion 7106 preferably is betweenabout 2 inches (50.8 mm) and about 5 inches (127 mm). In someembodiments, the length 7128 of the access device 7100, e.g., about 60mm, about 70 mm, about 80 mm, about 90 mm, about 100 mm, about 110, ormore than any of the foregoing dimensions, preferably is selected basedon the anatomy of the patient and/or the type of procedure to beperformed.

With reference to FIGS. 125-129, the proximal portion 7106 of the accessdevice 7100 includes a tube 7114. The distal portion 7106 of the accessdevice 7100 has an expandable skirt portion 7116. The skirt portion 7116preferably has a reduced profile configuration with an initial dimension7118 and corresponding cross-sectional area. The skirt portion 7116preferably is expandable to an enlarged configuration with a relativelylarger dimension 7120 and corresponding cross-sectional area. In oneembodiment, the skirt portion 7116 is coupled with the proximal portion7104. A rivet 7122, pin, or similar connecting device can be used tocouple the proximal and distal portions 7102, 7104. The rivet 7122preferably permits movement of the skirt portion 7116 relative to theproximal portion 7104. The skirt portion 7116 is shown coupled with theproximal portion in FIG. 129.

In the illustrated embodiment, the skirt portion 7116 is manufacturedfrom a resilient material, such as stainless steel. The skirt portion7116 preferably is manufactured so that it normally assumes an expandedconfiguration. The skirt portion 7116 preferably is sufficiently rigidthat it is capable of displacing the tissue surrounding the skirtportion 7116 as it expands. Depending upon the resistance exerted bysurrounding tissue, the skirt portion 7116 preferably is sufficientlyrigid to provide some resistance against the tissue to remain in theexpanded configuration. In some embodiments, one feature of the skirtportion 7116 is the provision of a shallow concave profile 7124 definedalong a distal edge of the skirt portion 7116, which allows for improvedplacement of the skirt portion 7116 with respect to body structures andsurgical instruments. In some embodiments, one or more portions of theskirt portion 7116, e.g., along the distal edge, are formed toaccommodate long implants or tools. For example, cut outs can beprovided on opposite sides of the distal edge of the skirt portion 7116to enable a fixation element to be at least partially extended out ofthe working space.

FIGS. 130-132 further illustrate the proximal portion 7104 of the accessdevice 7100, according to one embodiment. The length 7126 of theproximal portion 7104 of the access device 7100 preferably is betweenabout 1 inch (25.4 mm) and about 4 inches (101.6 mm) in one embodiment.The length 7104 of the proximal portion of the access device, e.g.,about 27 mm, about 37 mm, about 47 mm, about 57 mm, about 67 mm, orabout 77 mm, preferably is selected based on the anatomy of the patientand/or the type of procedure to be performed.

FIGS. 133-134 show distal skirt portions 7116 of the access device 7100according to one embodiment. The size and shape of the skirt portion7116 advantageously provides access to a surgical location when coupledwith the proximal portion of the access device and placed in an expandedconfiguration. In other embodiments, skirt portions 7116 have differentsizes and shapes. In some embodiments, the shape of the distal portion7106 of the access device 7100 can provide an oval shaped access areawhen expanded. In other embodiments, the shape of the distal portion7106 of the access device 7100 can provide any other oblong shapedaccess area when expanded. In some embodiments a locking mechanism 7130is provided on the distal portion 7106 of the access device 7100 as willbe described further below.

FIGS. 133-134 show right and left skirt portions 7148, 7150 in initialflattened configurations. FIG. 133 illustrates a right skirt portion7148 for an access device 7100 with an oval shaped cross section havingan expanded length 7120 of about 50 mm along the long axis. FIG. 134illustrates a cooperating left skirt portion 7150 for the access device7100. The skirt portions 7116 can be manufactured from sheets ofstainless steel having a thickness of about 0.007 inches (0.178 mm).Other materials, such as nitinol or plastics having similar properties,may also be used. The skirt portions 7148, 7150 preferably each have aprotruding portion 7132 along one of the sides for providing a lockingfeature, as will be described further below.

As discussed above, the skirt portions 7148, 7150 are coupled with theproximal portion 7104 with pivotal connections, such as rivets 7122. Afirst rivet hole 7134 and second rivet hole 7136 can be provided in eachof the right and left skirt portions 7148, 7150 to receive the rivets7122. In the illustrated embodiment, the right and left skirt portions7148, 7150 each have first and second free ends 4138, 4140 that aresecured by slidable connections, such as additional rivets 7142. In theillustrated embodiment, a first slot 7144 and a second slot 7146 aredefined in the right skirt portion 7148 near the free ends 7138, 7140respectively. In the illustrated embodiment, a first slot 7152 and asecond slot 7154 are defined in the left skirt portion 7150 near thefree ends 7138, 7140 respectively. With reference to FIGS. 133 134, inone embodiment, the first slots 7144, 7152 preferably are longer thanthe second slots 7146, 7154. The right and left skirt portions 7148,7150 preferably are configured so that a rivet 7142 that is positionedwithin the longer slot 7144 in the right skirt portion 7148 ispositioned in the shorter slot 7154 in the left skirt portion 7150.Similarly, a rivet 7142 that is positioned within the longer slot 7152in the left skirt portion 7150 is positioned in the shorter slot 7146 inthe right skirt portion 7148. The rivets 7142 are permitted to movefreely within the slots 7144, 7154, 7152, 7146. This slot and rivetconfiguration allows the skirt portions 7148, 7150 to move between thereduced profile configuration of FIGS. 123-124 and the expandedconfiguration of FIGS. 125-129. The skirt portion 7116 preferably canexpand to span up to three or more vertebrae, e.g., L4, L5, and S1. Thisarrangement enables multi-level procedures, such as multilevel fixationprocedures alone or in combination with a variety of other procedures.One of the rivets 7142 coupling the left and right skirt portions 7148,7150 together, along with a pair of washers 7156, is shown in FIG. 128.

In the illustrated embodiment, the access device 7100 has a lockingmechanism 7130. The distal portion 7106 is provided with a lock thatenables a user to selectively lock the distal portion 7106 into a stateof expansion. In some embodiments, the user can lock the distal portionin a contracted configuration. In the illustrated embodiment, a firstlocking mechanism 7130 is provided on a first side of the access device7100. A second locking mechanism preferably is provided on a second sideof the access device 7100. The locking mechanism 7130 can take manyforms. In one embodiment, the locking mechanism 7130 includes a firstlocking slot 7160, a second locking slot 7162, and a clip or lockingelement 7164 that can be moved (e.g., rotated, actuated, manipulated) tolock the access device 7100 in a desired configuration. In theillustrated embodiment, first and second locking slots 7160, 7168 aredefined in the right skirt portion 7148 near the free ends 7138, 7140.In the illustrated embodiment, first and second locking slots 7166, 7162are defined in the left skirt portion 7150 near the free ends 7138,7140. With reference to FIGS. 133-134, the first locking slots 7160,7166 preferably are longer than the second locking slots 7162, 7168. Thelonger slots 7160, 7166 preferably are curved or angled near an end ofthe slots. The shorter slots 7162, 7168 preferably are also curved. Inone embodiment, each of the shorter slots 7162, 7168 generally forms anarc. The right skirt portion 7148 has an opening 7170 positioned nearthe shorter slot 7168. The left skirt portion 7150 has an opening 7172positioned near the shorter slot 7162. The shorter curved slots 7162,7168 preferably are formed on or near protruding portions 7132 of theskirts.

FIGS. 135-137 illustrate a locking clip or locking element 7164,according to one embodiment. With reference to FIGS. 135-137, a lockingelement 7164, e.g., a lock, a stop, a tab, a flange, a clip, or a hook,preferably is coupled with one or more of the left and right skirtportions 7148, 7150. In the illustrated embodiment, the locking element7164 has a generally L-shaped configuration. The locking element 7164preferably is movable, e.g., rotatable, articulable, manipulatable, orpositionable, relative to one or more of the skirt portions 7148, 7150.As shown in FIGS. 135-137, the locking element has a base portion 7174,a tab portion 7176, and a disk portion 7178. The base portion 7174preferably has a length of about 0.21 inches (5.33 mm) and a thicknessof about 0.0155 inches (0.394 mm) in one embodiment. An opening 7180 isdefined in the base portion 7174. The opening 7180 preferably is sizedto receive a coupling member, such as, for example, a rivet 7182. In theillustrated embodiment, the opening 7180 preferably has a diameter ofabout 0.046 inches (1.17 mm). In some embodiments the opening 7180 canbe located generally centrally on the base portion 7174. The diskportion 7178 preferably extends from a first surface 7184 of the baseportion 7174. In the illustrated embodiment, the disk portion 7178extends from the first surface 7184 a distance of about 0.0155 inches(0.394 mm) and has a diameter of about 0.04 inches (1.02 mm). The diskportion 7178 preferably is positioned near a first end of the baseportion 7174. In some embodiments, the disk portion 7178 can be weldedto the base portion 7174. In the illustrated embodiment, the tab portion7176 is positioned generally normal to the base portion 7174 near asecond end of the base portion 7174. The tab portion 7176 preferablyextends about 0.055 inches (1.40 mm) from a second surface 7186 of thebase portion 7174 and has a thickness of about 0.0155 inches (0.394 mm).In one embodiment, the locking element 7164 is made of stainless steel.In some embodiments, the locking element 7164 can be fabricated bymachining or formed and welded.

With reference to FIGS. 125-127 and 133-134, in one embodiment, thelocking mechanism 7130 comprises the right and left skirt portions 7148,7150, the locking element 7164, one or more compression washers 7188(See FIGS. 127 and 138) and a rivet 7182. The locking element 7164preferably is coupled with the right skirt portion 7148 at the opening7170 on or near the protruding portion 7132 of the skirt using the oneor more compression washers 7188 and the rivet 7182. The locking element7164 preferably is positioned between the right and left skirt members7148, 7150 and oriented such that the first surface 7184 of the baseportion 7174 of the locking element 7164 faces toward the right skirtportion 7148. The disk portion 7178 preferably is positioned to facetoward the smaller arcuate slot 7168 on the protruding portion 7132 ofthe right skirt portion 7148. The locking element 7164 is sized andconfigured so that when the locking rivet 7182 is positioned in theopening 7180 of the locking element 7164 and also in the opening 7170 onthe right skirt portion 7148, the disk portion 7178 of the lockingelement 7164 can be positioned so that it extends into the smallerarcuate slot 7168 on the right skirt portion 7148. In the illustratedembodiment, the disk portion 7178 is oriented such that the disk portion7178 faces toward the outside of the access device 7100. The accessdevice 7100 preferably is also configured so that when the slidingrivets 7142 coupling the right and left skirt portions 7148, 7150 arepositioned within the appropriate slots, e.g., the rivet 7142 withinslots 7144 and 7154, the tab end 7176 of the locking mechanism 7130 canextend toward, and be positioned within, the longer curved or angledslot 7166 on the left skirt portion 7150. In the illustrated embodiment,the tab portion 7176 extends toward the inside of the access device7100. The locking element 7164 preferably is rotatably coupled with theright skirt portion 7148 at the opening 7170 with the one or morecompression members 7188 and the rivet 7182, as shown in FIG. 127.

When the access device 7100 is in the closed position, or the lowprofile position, the locking element 7164 preferably is rotated so thatthe tab portion 7176 is positioned within the longer portion of thelonger curved or angled slot 7166. In this configuration, the right andleft skirt portions 7148, 7150 are free to slide past one another intothe expanded configuration. When the access device 7100 is in theexpanded configuration, the tab portion 7176 of the locking element 7164can be rotated into the shorter curved or angled portion of the longerslot 7166. The locking element 7164 can be actuated, manipulated, orrotated using an instrument or in any other suitable manner to positionthe tab portion 7176 in the angled portion of the slot 7166. When thetab portion 7176 is engaged in the locked position, the sides of thecurved or angled portion of the longer slot 7166 act to restrain therelative movement of the overlapping skirt portions 7148, 7150 toselectively limit expansion or un-expansion of the distal portion 7106of the access device 7100. In some other embodiments, the relative sizesand configurations of the locking structures and mechanisms can vary.

In one application, the access device 7100 is used to provide minimallyinvasive access to the spine for a spinal procedure as described herein.The expansion and location of the access device 7100 may be confirmed byfluoroscopy. After the access device 7100 has been fully expanded, thelock can be articulated to lock or unlock the access device 7100.

FIGS. 139-150, illustrate another embodiment of an access device 7200.The structure and configuration of the access device shown in FIGS.139-150 is similar to that described in connection with FIGS. 123-138,except as shown or noted below. Like reference numerals have been usedto identify like features in the two embodiments, except that thereference numerals used with respect to FIGS. 139-150 will be in the“7200s” rather than the “7100s.”

As shown in FIGS. 139-150, the access device 7200 has a passage 7202with a generally oval shaped cross section. FIGS. 141-142 show theaccess device 7200 in an expanded configuration. In the illustratedembodiment, the access device 7200 has a distal portion 7206 thatexpands to a cross section having a width of about 24 mm and a length7220 of about 80 mm. The sizes and lengths associated with the accessdevice 7200 can vary. In some embodiments, a generally longercross-sectional length provides increased access for performing somesurgical procedures. FIGS. 149-150 show distal skirt portions 7216 ofthe access device 7200 according to one embodiment. The size and shapeof the skirt portion 7216 advantageously provides increased access to asurgical location in an expanded configuration. In other embodiments,skirt portions 7216 have different sizes and shapes. In someembodiments, the shape of the distal portion 7206 of the access device7200 can provide an oblong shaped access area when expanded. FIGS.149-150, show right and left skirt portions 7248, 7250 in initialflattened configurations. In the illustrated embodiment, the skirtportions 7248, 7250 are configured to form an access device 7200 havingan oval shaped cross section with an expanded length 7220 of about 80 mmalong the long axis. In the illustrated embodiment, a locking mechanism7230 generally similar to that described with respect to the embodimentshown in FIGS. 123-138 is provided.

IV. Additional Apparatuses Configured to be Coupled with Vertebrae

FIGS. 151-155 illustrate various embodiments of apparatuses that can becoupled with vertebrae in connection with a variety of surgicalprocedures, including those discussed herein.

FIGS. 151-153 illustrate an apparatus 8010 constructed according to oneembodiment. The apparatus 8010 includes a surgically implantablelongitudinal member or rod 8012 for maintaining bone portions, such asvertebrae of a spinal column, in a desired spatial relationship. Themember 8012 is connected with vertebrae of the spinal column byfasteners 8016.

The rod 8012 is made of a suitable biocompatible material and has alength which is at least sufficient to enable the rod to span at leasttwo vertebrae. The length of the rod 8012 in any particular installationwill depend upon the condition to be corrected and the number ofvertebrae to be held in a desired spatial relationship relative to eachother by the rod.

The rod 8012 (FIGS. 151-153) is connected to a respective vertebra bythe fastener 8016 made of a suitable biocompatible material. Thefastener 8016 (FIGS. 151-152) has a longitudinal axis 8018 and athreaded end portion 8022 having a course thread convolution 8024 whichengages the vertebra. A second end portion 8026 of the fastener 8016 isprovided with a spherical surface 8028. A recess 8032 (FIG. 151) isprovided on the end portion 8026 of the fastener 8016. The recess 8032receives a tool, such as the endoscopic screwdriver apparatus 660 shownin FIGS. 28-29, that applies torque to the fastener 8016 to turn thethread convolution 8024 into the vertebra.

The fastener 8016 (FIGS. 151-153) extends into a housing 8040 thatinterconnects the rod 8012 and the fastener 8016. The housing 8040 has afirst passage 8042 through which the rod 8012 extends. The housing 8040has a second passage 8044 with a longitudinal axis 8046 that extendstransverse to the passage 8042. The fastener 8016 extends through anopening 8050 in the housing 8040 and into the second passage 8044. Thespherical surface 8028 (FIG. 153) of the fastener 8016 engages a concavepart spherical surface 8052 of the housing 8040. Accordingly, thefastener 8016 is universally pivotable relative to the housing 8040 sothat the longitudinal axis 8018 of the fastener 8016 is positionable inany one of a plurality of angular positions relative to the longitudinalaxis 8046 of the passage 8044.

The passage 8044 (FIG. 153) is defined by a pair of first or upperaxially extending part cylindrical surfaces 8054 having a firstdiameter. The housing 8040 has a second or lower cylindrical surface8056 having a second diameter smaller than the first diameter. A taperedsurface 8058 extends from the first cylindrical surfaces 8054 to thesecond cylindrical surface 8056.

The housing 8040 (FIG. 153) includes a pair of upper portions 8060. Eachof the upper portions 8060 includes at least one thread 8062. The upperportions 8060 also include circumferentially extending grooves 8064. Thegrooves 8064 are defined by cylindrical surfaces 8066 extendinggenerally parallel to the longitudinal axis 8046 of the housing 8040.The surfaces 8066 have diameters larger than the diameter of cylindricalsurfaces 8054. Lower radially extending surfaces 8068 extend generallyperpendicular to the cylindrical surfaces 8066. The radially extendingsurfaces 8068 extend radially outward from and generally perpendicularto the axially extending cylindrical surfaces 8054. The threads 8062extend axially from upper surfaces 8071 of the housing 8040 to thegrooves 8064. Accordingly, the threads 8062 terminate axially above therod 8012 when the rod is connected to the housing 8040. The grooves 8064permit the threads 8062 to be easily formed in the housing 8040.

The housing 8040 (FIGS. 151-153) includes two diametrically opposedopenings 8072. The openings 8072 (FIG. 153) are defined by deformableradially inner portions or walls 8074. The walls 8074 are deformedradially inwardly after insertion of the fastener 8016. Dimples 8076 areformed in the walls 8074 to help retain the fastener in the housing8040.

A spacer 8080 is housed in the second passage 8044 of the housing 8040.The spacer 8080 (FIG. 153) has a lower portion 8082 engageable with thefastener 8016. A concave part spherical surface 8084 of the lowerportion 8082 engages the spherical surface 8028 of the fastener 8016.

An axially extending portion 8086 of the lower portion 8082 extends fromthe spherical surface 8084 and is spaced from the spherical surface 8028of the fastener 8016. The axially extending portion 8086 includes anarcuate surface 8088 extending from the spherical surface 8084. Anaxially extending cylindrical surface 8090 extends axially downward, asviewed in FIG. 3, from the arcuate surface 8088. The arcuate surface8088 and the cylindrical surface 8090 are spaced from the sphericalsurface 8028 of the fastener 8016. The axially extending portion 8086helps position the spacer 8080 in the housing 8040.

The spacer 8080 (FIGS. 151-153) has an upper portion 8090 with an uppersurface 8092 engageable with the rod 8012. The spacer 8080 has anaxially extending opening 8094 that extends through the upper portion8090 and the lower portion 8082. A tool, such as the endoscopicscrewdriver apparatus 660, extends through the opening 8094 to engagethe recess 8032 in the fastener 8016. The tool extends through theopening 8094 to apply torque to the fastener 8016 and connect thefastener to the vertebra.

The lower portion 8082 of the spacer 8080 (FIGS. 151 and 153) has afirst radially outer cylindrical surface 8096 with an outer diameterslightly smaller than the diameter of the lower cylindrical surface 8056of the housing 8040. The upper portion 8090 of the spacer 8080 includesa second radially outer cylindrical surface 8098 having a diametersmaller than the cylindrical surface 8096. A radially extending surface8100 extends from the cylindrical surface 8096 to the cylindricalsurface 8098.

A ring-shaped retaining or positioning member 8110 holds the spacer 8080in the housing 8040. The retaining member 8110 has a radially innercylindrical surface 8112 with a diameter slightly larger than theoutside diameter of the radially outer cylindrical surface 8098 on thespacer 8080. The retaining portion 8110 has a radially outer cylindricalsurface 8114 that engages the housing 8040. The outer cylindricalsurface 8114 has a diameter which is slightly smaller than the diameterof first or upper cylindrical surfaces 8054 of the housing 8040 andslightly larger than the diameter of second or lower cylindrical surface8056 of the housing. Accordingly, the retaining member 8110 is easilyinserted into the housing 8040. The retaining member 8110 engages thetapered surface 8058 of the housing 8040. The retaining member 8110 isthen press fit into engagement with the surface 8056 of the housing8040.

A ring-shaped spring member 8120 engages the retaining member 8110 andthe spacer 8080. The spring member 8120 engages the radially extendingsurface 8100 on the spacer 8080 to apply an axial force to the spacer toprevent relative movement between the fastener 8016 and the housing 8040when the rod 8012 is disengaged from the spacer and the spacer engagesthe fastener. The spring member 8120 urges the spacer 8080 axiallyrelative to the housing 8040 toward the fastener 8016. The spring member8120 urges the part spherical surface 8052 of the housing 8040 againstthe spherical surface 8028 of the fastener 8016. The part sphericalsurface 8084 of the spacer 8080 frictionally engages the sphericalsurface 8028 of the fastener 8016 and the spherical surface 8028 of thefastener frictionally engages the part spherical surface 8052 of thehousing 8040. The fastener 8016 and the housing 8040 are manuallymovable relative to each other by a surgeon when the rod 8012 isdisengaged from the spacer 8080 and the spring member 8120 applies theaxial force. The force applied by the spring member 8120 may be overcomeby the surgeon to move the housing 8040 relative to the fastener 8016.Accordingly, the housing 8040 can be positioned relative to the fastener8016 and held in position relative to the fastener by the spring member8120 without the rod engaging the spacer 8080.

The spring member 8120 (FIGS. 151 and 154) has an annular shape with anouter diameter smaller than the diameter of the lower cylindricalsurface 8056 of the housing 8040. The spring member 8120 has an innerdiameter larger than the outer cylindrical surface 8098 of the spacer8080. The spring member 8120 has an arched shape, as viewed in FIG. 5,when the spring member is disengaged from the spacer 8080 and theretaining member 8110. When the spring member 8120 is received betweenthe spacer 8080 and the retaining member 8110, the spring member iscompressed and applies an axial force to the spacer. The spring member8120 is formed by bending a flat ring to form the arched shape.Diametrically opposite sides of the spring member 8120 are bent towardeach other to form the arched shape.

The amount of axial force applied by the spring member 8120 to thespacer 8080 depends on the position of the retaining member 8110relative to the housing 8040 and the spacer. The retaining member 8110may be press-fit into the housing 8040 in any one of a plurality ofaxial positions relative to the housing. Accordingly, the amount ofaxial force applied by the spring member 8120 to the spacer 8080 may beadjusted to a desired force. The force applied by the spring member 8120increases as the retaining member 8110 gets closer to the radiallyextending surface 8100 on the spacer 8080.

The retaining member 8110 is also connected to the housing 8040 by apair of diametrically opposed circumferential welds 8122. The welds 8122may be laser welds that fixedly connect the retaining member 8110 to thehousing 8040. The laser welds 8122 may extend circumferentially aroundthe retaining member any desired distance. It is contemplated that anydesired number of welds 8122 may be used to connect the retaining member8110 to the housing 8040.

A clamping mechanism or cap screw 8124 (FIGS. 152 and 153) threadablyengages the threads 8062 on the housing 8040. The cap screw 8124 engagesand applies a force to the rod 8012 to press the rod against the spacer8080 and the spacer against the fastener 8016. The cap screw 8124 clampsthe rod 8012, the spacer 8080, and the housing 8040 to the fastener 8016to prevent relative movement between the fastener, the housing and therod. The force applied by the cap screw 8124 cannot be overcome by thesurgeon to move the housing 8040 relative to the fastener 8016.

The apparatus 8010 is assembled by inserting the fastener 8016 throughthe opening 8050 in the housing 8040 so that the spherical surface 8028of the fastener engages the part spherical surface 8052 of the housing.The spacer 8080 is inserted into the housing 8040 and into engagementwith the fastener 8016. The spring member 8120 is inserted into thesecond passage 8044 and into engagement with the spacer 8080. Theretaining member 8110 is inserted into the second passage 8044 and intoengagement with the spring member 8120. The retaining member 8110 isinserted into the passage to compress the spring member 8120 until thespring member applies the desired force to the spacer 8080. Theretaining member 8110 is press fit into the housing 8040 to retain thefastener 8016, the spacer 8080, and the spring member 8120 in thehousing 8040.

The walls 8074 of the housing 8040 are deformed radially inward to formthe dimples 8076, as shown in FIG. 153. The dimples 8076 are axiallyspaced from the retaining member 8110. Accordingly, the dimples 8076help retain the retaining member 8110, the spring member 8120, thespacer 8080, and the fastener 8016 in the housing 8040. The retainingmember 8110 is then welded to the housing 8040 to further help retainthe retaining member, the spring member 8120, the spacer 8080, and thefastener 8016 in the housing.

As discussed above, the apparatus 8010 is particularly well suited forminimally invasive procedures. In one such procedure, the apparatus 8010is applied to the spine through an access device or a retractor, such asone similar to the access device 5000, any of the other access devicesdescribed herein, and any of the access devices described in documentsincorporated by reference herein. A preliminary step in such a procedureis to deliver the access device, as discussed above. At least a portionof the access device optionally is expanded to increase access to asurgical location. In a one level fixation procedure, the access deviceprovides access to two adjacent vertebrae, e.g., the pedicles of twoadjacent vertebrae, as discussed above. Additional adjacent vertebraemay be exposed by an access device for procedures performed over longersurgical fields.

Thereafter, a tool, such as the endoscopic screwdriver apparatus 660, isinserted through the opening 8084 in the spacer 8080 and into the recess8032 in the fastener 8016. The fastener 8016 preferably is advancedthrough the access device to the surgical locations. Torque is appliedto the fastener 8016 to turn the thread convolution 8024 into thevertebra. Once the fastener 8016 is connected with the vertebra, thehousing 8040 can be positioned relative to the fastener. The springmember 8120 maintains the position of the housing 8040 relative to thefastener 8016 while the rod 8012 is disengaged from the spacer 8080. Byenabling the housing 8040 to be maintained in a selected positionrelative to the fastener 8016, the surgeon's hands are free tomanipulate other tools or implants to complete the procedure. Thisfeature simplifies and shortens the procedure, benefiting the patientand the surgeon.

Once the housing 8040 is positioned relative to the fastener 8016, therod 8012 is placed into the passage 8042 and in engagement with thespacer 8080. Placing the rod 8012 in the passage 8042 may be facilitatedby a suitable tool, such as the grasper apparatus 700, discussed above.Also, placing the rod 8012 may include additional optional steps relatedto a spondy reduction procedure. Spondy procedures and tools configuredto perform them are described in PCT Application No. PCT/US03/27879,filed Sep. 5, 2003, which is hereby expressly incorporated by referenceherein in its entirety. The cap screw 8124 is threaded into the housing8040 and into engagement with the rod 8012. The endoscopic screwdriverapparatus 660 may be used to thread the cap screw 8124 into the housing8040. The cap screw 8124 clamps the rod 8012, the spacer 8080, and thehousing 8040 to the fastener 8016 to prevent movement of the fastenerrelative to the housing. Alternatively, the fastener 8016 may beconnected to the vertebra prior to the spacer 8080, the spring member8120, and the retaining member 8110 being inserted into the housing8040.

If the apparatus 8010 is deployed in a minimally invasive procedure,delivery of the cap screw 8124 may be facilitated by the guide apparatus800 or other similar tool. Prior to clamping the cap screw 8124,additional procedures that manipulate the position of the apparatus 8010relative to another apparatus 8010 or the position of adjacent vertebraemay be performed. Such procedures include compression and distractionprocedures. Useful tools for performing such procedures include thecompressor-distractor instrument 900 and additionalcompressor-distractor instruments described in U.S. Publication No. 20030236529 A1 and PCT Application No. PCT/US03/020003, filed Jun. 24, 2003,which is hereby expressly incorporated by reference herein in itsentirety.

PCT Application No. US03/04361, filed Feb. 13, 2003, and U.S. patentapplication Ser. No. 10/926,840, filed Aug. 26, 2004 are incorporatedherein entirely by reference.

FIG. 156 illustrates another embodiment of an apparatus similar to theother apparatuses described herein, except as noted below. In theembodiment shown in FIG. 156, a cap screw 9124 includes a boss 9126 thatextends from the threads 9128 of the cap screw 9124 to a lower surface9130 of the cap screw 9124. The boss 9126 may include a substantiallycylindrical surface 9132 extending between the threads 9128 and thelower surface 9130. The boss 9126 preferably is of sufficient length anddiameter to initially align the cap screw 9124 with a housing 9040.Advantageously, initial alignment of the cap screw 9124 with the housing9040 reduces the occurrence of cross-threading. One of skill in the artwill appreciate that the boss 9126 need not comprise a substantiallycylindrical surface 9132 to achieve the purpose of providing initialalignment and that bosses of other shapes may similarly provide thedesired initial alignment. When the rod 9012 is connected to the housing9040, the length of the boss 9126 may allow the rod 9012 to be entirelybelow a pair of circumferentially extending grooves 9064 formed in apair of upper portions 9060 of the housing 9040 below the threads 9062,as illustrated in FIG. 156. Thus, both the threads 9062 and the grooves9064 of the upper portions 9060 of the housing 9040 are provided abovethe level of the rod 9012 when the rod sits in the housing 9040.

The caps screw 9124 also includes a recess 9166. The recess 9166 may behex-shaped, and receives a tool that applies torque to the cap screw9124. In the embodiment illustrated in FIG. 156 the recess 9166 does notpass entirely through the cap screw 9166, such that the cap screw has asolid lower surface.

FIGS. 157-160 illustrates another embodiment of an apparatus similar tothe other apparatuses described herein, except as noted below. In theembodiment shown in FIGS. 157-160, a cap screw 10124 has an asymmetricalbottom surface configuration to provide differing contact points onopposite sides of the passage receiving the rod. In one embodiment, thecap screw comprises a first bottom protrusion 10130 and a second bottomprotrusion 10132. The first bottom protrusion 10130 is generally annularforming a ring, facing downward as shown in FIG. 157. The second bottomprotrusion 10132 is generally semi-annular and lies substantially in thesame plane as the first bottom protrusion 10130. The second bottomprotrusion 10132 also faces downward, and preferably defines an arc withthe same center as that of the first bottom protrusion, but with asmaller radius. In one embodiment, the second bottom protrusion 10132may define an arc of about 180 degrees. In other embodiments, the secondbottom protrusion 10132 can be generally annular. As illustrated in FIG.160, when the cap screw 10124 is tightened the first bottom protrusion10130 and second bottom protrusion 10132 engage the rod 10012. Asillustrated, the cap screw 10124 engages the rod at three points, two ofsuch points being provided on one side of the passage in which the rodsits (through engagement of surfaces 10130 and 10132) and the third ofsuch points being provided on the other side of the passage (throughengagement of surface 10130). Having a plurality of contact pointsbetween the rod and the cap advantageously distributes the forces on therod. In some embodiments, the bottom surface of the cap screw can beconfigured to have 2, 3, 4, 5, 6 or more contact points with the rod,with said contact points being provided asymmetrically on the rod onopposite sides of the passage.

It is generally desired that the cap screw 10124 securely grip the rod10012 to prevent movement of the rod 10012 relative to the cap screw10124. While tightening the cap screw 10124 sufficiently to embed thebottom protrusions into the rod 10012 may assist in preventing relativemovement of the two, it may also have the undesirable effect of reducingthe fatigue strength of the rod 10012 at any point of engagement betweencap screw 10124 and rod 10012 particularly where the rod 10012 is intension. In the embodiments described herein, asymmetric engagementallows the bottom protrusions on the side of the cap screw with fewercontact points to further embed themselves into the rod 10012, while theforces on the side with more contact points are distributed over alarger area and therefore embed themselves into the rod 10012 to alesser degree. The cap screw can then be desirably positioned such thatthe side of the cap screw 10124 with more contact points preferablyengages the rod 10012 at a location of greater surface tension than theside of the cap screw 10124 with fewer contact points. For example, theside of the cap screw with more contact points may be positioned towardthe inside of a multi-level assembly, such that the side with morecontact points is toward an adjacent screw. Proper alignment can beensured using markers on an upper surface of the cap screw. Thus, thecap screw 10124 may prevent movement of the rod 10012 relative to thecap screw 10124 while maximizing the fatigue strength of the rod 10012.

FIGS. 161 and 162 illustrate another embodiment of an apparatus similarto the other apparatuses described herein, except as noted below. In theembodiment shown in FIGS. 161 and 162, the housing 11040 comprises apassage 11044 for receiving a fastener that, near its opening 11050, hasa first generally frustoconical surface 11134 and a second generallyfrustoconical surface 11136 provided below the first generallyfrustoconical surface 11134. Relative to a longitudinal axis of thehousing 11040, the first generally frustoconical surface 11134 is lessinclined than the second generally frustoconical surface 11136. In someembodiments the first generally frustoconical surface 11134 is inclinedat between about 2° and 15° and the second generally frustoconicalsurface 11136 is inclined at between about 15° and 30° or more. In otherembodiments the first generally frustoconical surface 11134 is inclinedat between about 5° and 30° and the second generally frustoconicalsurface 11136 is inclined at between about 15° and 60° or more. In stillother embodiments the first generally frustoconical surface 11134 isinclined at between about 10° and 45° and the second generallyfrustoconical surface 11136 is inclined at between about 20° and 60° ormore. In one embodiment, the first generally frustoconical surface 11134preferably is inclined at about 11° relative to the longitudinal axis ofthe housing 11040. Accordingly, the frustoconical surface 11134 mayextend at an angle of 79° relative to a line extending perpendicular tothe longitudinal axis of the housing 11040. The second generallyfrustoconical surface 11136 preferably is inclined at about 26° relativeto a longitudinal axis of the housing 11040. Accordingly, thefrustoconical surface 11136 may extend at an angle of 64° relative to aline extending perpendicular to the longitudinal axis of the housing11040.

A lower cylindrical surface 11056, the first generally frustoconicalsurface 11134, and the second generally frustoconical surface 11136 areseparated by a pair of transition surfaces 11138. The transitionsurfaces 11138 may be curved, as illustrated. Another cylindricalsurface may be provided below the second generally frustoconical surface11136. The first generally frustoconical surface 11134 and the secondgenerally frustoconical surface 11136 engage a fastener, not illustratedin FIGS. 161 and 162, similar to the fasteners illustrated and describedin association with the preceding embodiments. Such engagementadvantageously distributes forces on the fastener when compressedcompared with previous designs, illustrated in FIG. 163, wherein thehousing 12040 comprises a generally spherical surface 12052 providingthe only engaging surface. When the concave generally spherical surface12052 engages a convex spherical surface, they only contact at limitednumber of points and rather than over the entire surface becausemanufacturing processes are unable to produce surfaces that areperfectly spherical. The number and locations of the points of contactbetween two generally spherical surfaces may be difficult to predict. Incontrast, the embodiment of the apparatus illustrated in FIGS. 161 and162 advantageously provides a greater number of points of contact withmore predictable locations.

One of skill in the art will appreciate that engagement may occur atmore than two surfaces. For example, FIG. 164 illustrates anotherembodiment of an apparatus similar to the other apparatuses describedherein, except as noted below. In the embodiment shown in FIG. 164, thehousing 13040 comprises a first generally frustoconical surface 13134, asecond generally frustoconical surface 13136, and a third generallyfrustoconical surface 13140. Relative to a longitudinal axis of thehousing 13040, the first generally frustoconical surface 13134 is lessinclined than the second generally frustoconical surface 13136, and thesecond generally frustoconical surface 13136 is less inclined than thethird generally frustoconical surface 13140. The first generallyfrustoconical surface 13134 preferably is inclined at about 2° relativeto the longitudinal axis of the housing 13040. The second generallyfrustoconical surface 13136 preferably is inclined at about 9° relativeto a longitudinal axis of the housing 13040. The third generallyfrustoconical surface 13140 preferably is inclined at about 17° relativeto a longitudinal axis of the housing 13040. A pair of transitionsurfaces 13138 preferably are located between the first generallyfrustoconical surface 13134, the second generally frustoconical surface13136, and the third generally frustoconical surface 13140. Thetransition surfaces 13138 may be grooves.

One of skill in the art will further appreciate that engagement mayoccur at more than three surfaces. For example, FIG. 165 illustratesanother embodiment of an apparatus similar to the other apparatusesdescribed herein, except as noted below. In the embodiment shown in FIG.165, the housing 14040 comprises a first generally frustoconical surface14134, a second generally frustoconical surface 14136, a third generallyfrustoconical surface 14140, a fourth generally frustoconical surface14142, and a fifth generally frustoconical surface 14144. Relative to alongitudinal axis of the housing 14040, the first generallyfrustoconical surface 14134 is less inclined than the second generallyfrustoconical surface 14136, which is less inclined than the thirdgenerally frustoconical surface 14140, which is less inclined than thefourth generally frustoconical surface 14142, which is less inclinedthan fifth generally frustoconical surface 14144. The first generallyfrustoconical surface 14134 preferably is inclined at about 3° relativeto the longitudinal axis of the housing 14040. The second generallyfrustoconical surface 14136 preferably is inclined at about 6° relativeto a longitudinal axis of the housing 14040. The third generallyfrustoconical surface 14140 preferably is inclined at about 10° relativeto a longitudinal axis of the housing 14040. The fourth generallyfrustoconical surface 14142 preferably is inclined at about 14° relativeto a longitudinal axis of the housing 14040. The fifth generallyfrustoconical surface 14144 preferably is inclined at about 18° relativeto a longitudinal axis of the housing 14040.

FIG. 166 illustrates another embodiment of an apparatus similar to theother apparatuses described herein, except as noted below. In theembodiment shown in FIG. 166, the housing 15040 comprises a firstgenerally frustoconical surface 15134 and a second generallyfrustoconical surface 15136 separated by a transition surface 15138. Thetransition surface 15138 preferably is a groove. Relative to alongitudinal axis of the housing 15040, the first generallyfrustoconical surface 15134 is less inclined than the second generallyfrustoconical surface 15136. The first generally frustoconical surface15134 preferably is inclined at about 4° relative to the longitudinalaxis of the housing 15040. The second generally frustoconical surface15136 preferably is inclined at about 16° relative to a longitudinalaxis of the housing 15040.

It will be recognized from the embodiments described above, specificallythose shown in FIGS. 161-166, that the engagement between a housing anda fastener may occur at one or more generally frustoconical surfaces.Two or more generally frustoconical surfaces may be separated by one ormore transition surfaces, which may include either radii, grooves,inclined surfaces or any combination thereof.

FIGS. 167-170 illustrate an apparatus 16010 constructed according toanother embodiment. The apparatus 16010 includes a rod 16012 connectedwith vertebrae of the spinal column by fasteners 16016. The fastener16016 has a longitudinal axis 16018

The fastener 16016 extends into a housing 16040 that interconnects therod 16012 and the fastener 16016. The housing 16040 has a first passage16042 through which the rod 16012 extends. The housing 16040 has asecond passage 16044 with a longitudinal axis 16046 that extendstransverse to the passage 16042. The housing 16040 has apertures 16152extending parallel to passage 16042. Housing 16040 preferably has fourapertures 16152 consisting of two pairs of coaxial apertures. Theapertures 16152 may open to both the second passage 16044 and to theexterior of housing 16040.

Each of a pair of jaws 16146 has a proximal end 16158 and a distal end16160. An upper contact surface 16156 is located near the proximal end16158 of each jaw 16146. The upper contact surfaces 16156 preferably aregenerally part conical. A lower contact surface 16154 is located nearthe distal end 16160 of each jaw 16146. The lower contact surfaces 16154preferably are generally part spherical. A medial surface 16164 islocated between the upper contact surface 16156 and the lower contactsurface 16154, extending toward the other jaw. The medial surfaces 16164preferably are generally cylindrical. Each jaw includes an aperture16150 extending transversely through each jaw. The aperture may or maynot pass entirely through the jaw 16146. Plural apertures that do notpass entirely through the jaw 16146 may replace one aperture that passesentirely through the jaw 16146.

The jaws 16146 are generally disposed within housing 16040. The jaws16146 may protrude through an opening (not shown) in a lower end of thehousing 16040. The jaws 16146 are retained in housing 16040 by a pair ofpins 16148 that extend through the apertures 16150 in jaws 16146 and theapertures 16152 in housing 16040. The apparatus 16010 may comprise morethan two pins 16148. The jaws 16146 may rotate generally about pins16148.

The fastener 16016 extends between the jaws 16146 into the secondpassage 16044 through the opening (not shown) in the housing 16040. Aspherical surface 16028 of the fastener 16016 engages the lower contactsurfaces 16154 of jaws 16146. Accordingly, the fastener 16016 isuniversally pivotable relative to the housing 16040 so that thelongitudinal axis 16018 of the fastener 16016 is positionable in any oneof a plurality of angular positions relative to the longitudinal axis ofthe passage 16044. In some embodiments, the range of angular positionsis broader in a direction along the rod 16012 than the range of angularpositions in a direction transverse to rod 16012. Preferably, the rangeof angular positions in a direction along the rod 16012 is about 120°and the range of angular positions in a direction transverse to rod16012 is about 60°. The ability of an assembly comprising multipleapparatuses 16010 having in common a rod 16012 to conform to variedanatomy advantageously improves as the range of angular positions in adirection along the rod 16012 is broadened.

The housing includes a pair of upper portions 16060. Each of the upperportions 16060 includes at least one thread 16062. A cap screw 16124 hasat least one thread 16128 that engages the threads 16062 on the housing16040. The cap screw 16124 includes a boss 16126 that extends below thethreads 16128 of the cap screw 16124. The boss 16126 has a contactsurface 16162. The contact surface 16162 preferably is generallyfrustoconical, but may also be generally spherical or other shapes. Thecontact surface 16162 engages the upper contact surfaces 16156 of thejaws 16146 as the cap screw 16124 is tightened. Tightening the cap screw16124 also causes the lower contact surfaces 16154 of jaws 16146 tosecurely grasp the spherical surface 16028 of the fastener 16016. Thecap screw 16124 also engages the rod 16012 and forces it against eitherthe housing 16040, the medial surfaces 16164 of the jaws 16146, or both.The cap screw 16124 clamps the rod 16012 and the housing 16040 to thefastener 16016 to prevent relative movement between the fastener, thehousing and the rod. The force applied by the cap screw 16124 cannot beovercome by the surgeon to move the housing 16040 relative to thefastener 16016.

FIGS. 171 and 172 illustrate another embodiment of an apparatusincorporating features described above, and including additionalfeatures as described below. The apparatus includes a surgicallyimplantable longitudinal member or rod 17012 for maintaining boneportions, such as vertebrae of a spinal column, in a desired spatialrelationship. The member 17012 is connected with vertebrae of the spinalcolumn by fasteners 17016, such as described above.

The fastener 17016 extends into a housing 17040 that interconnects therod 17012 and the fastener 17016, and is pivotable relative to thehousing 17040 so that the longitudinal axis of the fastener 17016 ispositionable in any one of a plurality of angular positions relative tothe longitudinal axis 17046 of the housing 17040. A spacer 17080 ispositioned in the housing, with a lower portion engageable with thefastener 17016. The spacer 17080 has an upper portion with an uppersurface engageable with the rod 17012. A ring-shaped retaining orpositioning member 17110 holds the spacer 17080 in the housing 17040. Aring-shaped spring member 17120 engages the retaining member 17110 andthe spacer 17080, and a pair of diametrically opposed circumferentialwelds 17122 may connect the retaining member 17110 to the housing 17040.Further details regarding the housing 17040, spacer 17080, retainingmember 17110, spring member 17120 and welds 17122 are described above.

As shown in FIG. 172, the lower portion of the housing 17040 comprises apassage having a cylindrical surface 17056 which preferably extendsdownwardly from grooves 17064 formed in an upper portion of the housing.At a lower end of cylindrical surface 17056, the inner surface of thepassage transitions to a radial surface 1714, turning about 90 degreesto a horizontal surface 17142. The horizontal surface terminates at acircumferential edge 17148, which engages the spherical surface 17028 ofthe fastener 17016. Below the circumferential edge 17148 is a verticalor cylindrical surface 17144, and below cylindrical surface 17144 is alinearly tapered surface 17146 that increases in diameter from an upperend to the bottom of the housing. As illustrated in FIG. 172, thespherical surface 17028 of the fastener 17016 preferably does not engagethe cylindrical surface 17056, and only engages the housing at thecircumferential edge 17148.

The various devices, methods and techniques described above provide anumber of ways to carry out the invention. Of course, it is to beunderstood that not necessarily all objectives or advantages describedmay be achieved in accordance with any particular embodiment describedherein. Also, although the invention has been disclosed in the contextof certain embodiments and examples, it will be understood by thoseskilled in the art that the invention extends beyond the specificallydisclosed embodiments to other alternative embodiments and/or uses andobvious modifications and equivalents thereof. Accordingly, theinvention is not intended to be limited by the specific disclosures ofpreferred embodiments herein.

Many of the systems, apparatuses, methods, and features described hereincan be combined with many of the systems, apparatuses, methods andfeatures disclosed in the following patents and patent applications. Theentire disclosure of all of the following patents and patentapplications is hereby incorporated by reference herein and made a partof this specification: U.S. Pat. No. 6,361,488 (issued Mar. 26, 2002),U.S. Pat. No. 6,530,880 (issued Mar. 11, 2003), U.S. Pat. No. 6,648,888(issued Nov. 18, 2003), U.S. Pat. No. 6,652,553 (issued Nov. 25, 2003),U.S. Pat. No. 6,641,583 (issued Nov. 4, 2003), U.S. Pat. No. 6,554,832(issued Apr. 29, 2003), U.S. Pat. No. 6,673,074 (issued Jan. 6, 2004),U.S. patent application Ser. No. 09/821,666 (filed Mar. 29, 2001,published Oct. 3, 2002 as Publication No. U.S. 2002/0143328A1), Ser. No.09/824,411 (filed Apr. 2, 2001, published Oct. 3, 2002 as PublicationNo. U.S. 2002/0143330A1), Ser. No. 09/921,326 (filed Aug. 2, 2001,published Feb. 6, 2003 as Publication No. U.S. 2003/0028191A1), Ser. No.09/940,402 (filed Aug. 27, 2001, published Feb. 27, 2003 as PublicationNo. US 2003/0040656A1), Ser. No. 10/075,668 (filed Feb. 13, 2002,published Aug. 14, 2003 as Publication No. U.S. 2003/0153911A1), Ser.No. 10/087,489 (filed Mar. 1, 2002, published Sep. 4, 2003 asPublication No. U.S. 2003/0167058A1), Ser. No. 10/178,875 (filed Jun.24, 2002, published Dec. 25, 2003 as Publication No. U.S.2003/0236529A1), Ser. No. 10/280,489 (filed Oct. 25, 2002, publishedApr. 17, 2003 as Publication No. US 2003/0073998A1), Ser. No. 10/280,799(filed Oct. 25, 2002), Ser. No. 10/361,887 (filed Feb. 10, 2003,published Aug. 14, 2003 as Publication No. US 2003/0153927A1), Ser. No.10/969,788 (filed Oct. 20, 2004, published Aug. 4, 2005 as PublicationNo. 2005/017155), 10/483,605 (published Sep. 9, 2004 as Publication No.2004/0176766), Ser. No. 10/658,736 (filed Sep. 9, 2003, published Jul.8, 2004 as Publication No. US 2004/0133201), Ser. No. 10/678,744 (filedOct. 2, 2003, published Apr. 7, 2005 as Publication No. US 2005/0075540,Ser. No. 10/693,815 (filed Oct. 24, 2003, published Apr. 28, 2005 asPublication No. US 2005/0090822), Ser. No. 10/693,250 (filed Oct. 24,2003, published on Apr. 28, 2005 as Publication No. US 2005/0090899),Ser. No. 10/693,663 (filed Oct. 24, 2003, published on Apr. 28, 2005 asPublication No. US 2005/0090833), Ser. No. 10/842,651 (filed May 10,2004, published on Apr. 7, 2005 as Publication No. US 2005/0075644),Ser. No. 10/845,389 (filed May 13, 2004, published on Nov. 18, 2004 asPublication No. US 2004/0230100), Ser. No. 10/969,293, filed Oct. 20,2004, published on Apr. 20, 2006 as Publication No. US 2006/0084981),Ser. No. 11/094,822 (filed Mar. 30, 2005, published on Nov. 10, 2005 asPublication No. US 2005/0251192), Ser. No. 10/926,579 (filed Aug. 26,2004, published Dec. 8, 2005 as Publication No. US 2005/0273131), Ser.No. 10/926,840 (filed Aug. 26, 2004, published Dec. 8, 2005 asPublication No. US 2005/0273132), Ser. No. 10/927,633 (filed Aug. 26,2004, published Dec. 8, 2005 as Publication No. US 2005/0273133), Ser.No. 10/969,124 (filed Oct. 20, 2004, published May 19, 2005 asPublication No. US 2005/0107789), Ser. No. 10/972,987 (filed Oct. 25,2004, published Nov. 3, 2005 as Publication No. US 2005/0245942), Ser.No. 11/241,811 (filed Sep. 30, 2005, published Mar. 30, 2006 asPublication No. US 2006/0069404), Ser. No. 11/238,109 (filed Sep. 27,2005), Ser. No. 11/238,109 (filed Sep. 27, 2005), U.S. ProvisionalApplications No. 60/471,431 (filed May 16, 2003), 60/497,763 (filed Aug.26, 2003), 60/497,822 (filed Aug. 26, 2003), 60/513,796 (filed Oct. 22,2003), 60/513,013 (filed Oct. 23, 2003), 60/514,559 (filed Oct. 24,2003), 60/545,587 (filed Feb. 18, 2004), 60/558,296 (filed Mar. 31,2004), 60/579,643 (filed Jun. 15, 2004), and 60/625,782 (filed Nov. 5,2004).

1. An apparatus comprising: a longitudinal member connectable with abone portion; a fastener having a longitudinal axis and engageable withthe bone portion to connect said longitudinal member to the boneportion; a housing having a first passage configured to receive saidlongitudinal member, said housing having a second passage with alongitudinal axis extending transverse to said first passage, saidfastener extending through an opening in said housing into said secondpassage and being moveable relative to said housing, said second passageof said housing having at least first and second generally frustoconicalsurfaces for engagement with said fastener, said first and secondgenerally frustoconical surfaces extending in the same direction withthe first generally frustoconical surface being less inclined relativeto the longitudinal axis of the second passage than the second generallyfrustoconical surface, said longitudinal axis of said fastener beingpositionable in any one of a plurality of angular positions relative tosaid longitudinal axis of said second passage; a spacer received in saidsecond passage of said housing and engageable with said fastener andsaid longitudinal member; and a clamping mechanism configured to clampsaid longitudinal member, said spacer and said housing to said fastenerto prevent movement of said fastener relative to said housing.
 2. Theapparatus of claim 1, wherein the fastener comprises a spherical surfaceengageable with one or more of the generally frustoconical surfaces ofthe second passage of the housing.
 3. The apparatus of claim 1, whereinthe fastener extends from a distal end of the housing, the secondgenerally frustoconical surface being nearer than the first generallyfrustoconical surface to the distal end of the housing.
 4. The apparatusof claim 3, wherein the first generally frustoconical surface isinclined at between about two degrees and fifteen degrees and the secondgenerally frustoconical surface is inclined at between about fifteendegrees and thirty degrees relative to the longitudinal axis of thesecond passage of the housing.
 5. The apparatus of claim 3, wherein thefirst generally frustoconical surface is inclined at between about fivedegrees and thirty degrees and the second generally frustoconicalsurface is inclined at between about fifteen degrees and sixty degreesrelative to the longitudinal axis of the second passage of the housing.6. The apparatus of claim 3, wherein the first generally frustoconicalsurface is inclined at between about ten degrees and forty-five degreesand the second generally frustoconical surface is inclined at betweenabout twenty degrees and sixty degrees relative to the longitudinal axisof the second passage of the housing.
 7. The apparatus of claim 1,wherein the first generally frustoconical surface and the secondgenerally frustoconical surface are separated by a transition surface.8. The apparatus of claim 7, wherein the transition surface is curvate.9. The apparatus of claim 7, wherein the transition surface comprises agroove.
 10. The apparatus of claim 1, wherein the second passage of thehousing further comprises one or more cylindrical surfaces.
 11. Theapparatus of claim 10, wherein the generally frustoconical surfaces arebetween two cylindrical surfaces of the second passage of the housing.12. The apparatus of claim 11, wherein the generally frustoconicalsurfaces are separated from the cylindrical surfaces by transitionsurfaces.
 13. The apparatus of claim 1, wherein the second passage ofthe housing further comprises a third generally frustoconical surface,the second generally frustoconical surface being less inclined than thethird generally frustoconical surface relative to the longitudinal axisof the second passage of the housing.
 14. The apparatus of claim 13,wherein the fastener extends from a distal end of the housing, the thirdgenerally frustoconical surface being nearer than the second generallyfrustoconical surface to the distal end of the housing, the secondgenerally frustoconical surface being nearer than the first generallyfrustoconical surface to the distal end of the housing.
 15. Theapparatus of claim 13, wherein a transition surface is located betweenthe second generally frustoconical surface and the third generallyfrustoconical surface.
 16. The apparatus of claim 13, wherein the secondpassage of the housing further comprises a fourth generallyfrustoconical surface and a fifth generally frustoconical surface, thethird generally frustoconical surface being less inclined than thefourth generally frustoconical surface relative to the longitudinal axisof the second passage of the housing, the fourth generally frustoconicalsurface being less inclined than the fifth generally frustoconicalsurface relative to the longitudinal axis of the second passage of thehousing.
 17. The apparatus of claim 16, wherein the fastener extendsfrom a distal end of the housing, the fifth generally frustoconicalsurface being nearer than the fourth generally frustoconical surface tothe distal end of the housing, the fourth generally frustoconicalsurface being nearer than the third generally frustoconical surface tothe distal end of the housing, the third generally frustoconical surfacebeing nearer than the second generally frustoconical surface to thedistal end of the housing, the second generally frustoconical surfacebeing nearer than the first generally frustoconical surface to thedistal end of the housing.
 18. An apparatus for connecting alongitudinal member with a bone portion, comprising: a fastener having alongitudinal axis and engageable with a bone portion, the fastenerhaving a spherical surface; a housing having a passage, said fastenerextending through an opening in said housing into said passage, saidpassage having at least two generally frustoconical surfaces, eachconfigured to contact the spherical surface of said fastener.
 19. Theapparatus of claim 18, wherein the fastener is movable in any one of aplurality of angular positions relative to the housing.
 20. Theapparatus of claim 18, wherein the housing further comprises a channelfor receiving the longitudinal member.
 21. The apparatus of claim 20,further comprising a clamping mechanism configured to clamp thelongitudinal member to the fastener to prevent relative movement of thefastener relative to the longitudinal member.
 22. The apparatus of claim18, further comprising a spacer received in said passage of said housingand engageable with said fastener and said longitudinal member.
 23. Theapparatus of claim 22, further comprising a retaining member to retainsaid spacer and said fastener in said housing.